This guide is designed to assist the user in becoming quickly familiar with the capabilities of PEW, its interface and how the program is used.

Transcription

1 PEW User Guide

2 About this document This guide is designed to assist the user in becoming quickly familiar with the capabilities of PEW, its interface and how the program is used. It has been produced to the recommendations of British Standard BS7649 Guide to the design and preparation of documentation for users of application software. Trademarks All trademarks acknowledged.. Associated PEL Support Services Documents PEW Reference Guide: This document summarises the mathematical theory used by the PEW program. Contacting PEL Support Services This program is developed, maintained and supported by PEL Support Services, ABB. We run a Hotline telephone and service to answer any queries about PEW. Please let us have any suggestions on how you feel we could improve PEW. You can contact us by any of the following routes: By Telephone: ++44 (0) By Fax: ++44 (0) By By Post: pel.support@gb.abb.com PEL Support Services ABB Limited. Daresbury Park Daresbury Warrington Cheshire WA4 4BT United Kingdom. Owner: M. G. Pass, ABB. Approved By: M. G. Pass, ABB. Document Version / Issue Date: Version September 2012 Software Version PEW Last Amended Date: 07 September 2012 Last Amended By: J. Galligan, ABB. Copyright ABB. All rights reserved. No part of this publication may be reproduced or transmitted in any form, or by means, electronic, mechanical, photocopying, recording or otherwise without the prior written permission of ABB. Page 2 of 86 PEW User Guide

3 Change history This table records the changes made to each new revision of this document. Changes to approved issues are indicated by a double revision bar on the outer margin next to the text. This is an example. Revision Date Description of change July 2000 First Approved Issue Feb 2001 Second Approved Issue comprising the following: Deleted: Text in Appendix C.1 Vessel Calibration input data End dimensions. New: Figure 20 and accompanying bullets points below. New: Appendix sections C.3 to C March 2001 Third Approved Issue (ABB logo attached) Oct 2002 Fourth Approved Issue (Industrial IT logo & paragraph added, Eutech removed, Front page modified) October 2005 Removed Industrial IT logo September 2012 Added PPDS Calculator section. Properties calculator added to tutorial. Removed images for Windows functions (calculator and save dialog) PEW User Guide Page 3 of 86

4 Contents 1. PEW User Guide Introduction Principle features of PEW PEW Calculations Fluid Flow Heat Transfer Mixing Equipment How this guide is structured The PEW User Interface The PEW start up screen Calculation Type Inputs Forms Fluid Flow Inputs Incompressible Compressible Gravity Flow Manifold T-junction Symmetrical T-junction Expansion/Contraction Orifice Restrictor Two Phase Flow Heat Transfer Inputs Heat Transfer Coefficients Pipe Heat Loss Vessel Heat Loss Batch Heating/Cooling Simple Heat Exchanger Tank Solar Heating Finned Tube Mixing Inputs Vortex Profile Power Numbers Speed/Power curves Equipment Inputs Vessel Calibration Calculation Type Fittings Form Calculation Types Results Forms Handling Calculation Results Printing Results Creating a Graph Creating a Summary Table PEW Menus Project Menu Calculation Menu Edit Menu Summary Menu Graph Menu Units Menu Tools Menu Pipe Inner Diameter Calculator Molecular Weight Calculator K-value Calculator Pipe Roughness Calculator Calculator Page 4 of 86 PEW User Guide

5 Text Editor Calculate Physical Properties Calculate Physical Property Window Menu Help Menu The PEW Toolbar PEW Tutorial General Solving the Network Starting PEW Selecting the Calculation type Entering pipework and losses data on the Inputs form Entering data on the Fittings form Calculating fluid properties and process conditions data Performing the Calculation Repeating the calculation for other values Plotting the Graph Creating a Summary Table Saving a PEW file Figures Figure 1 PEW start up screen Figure 2 Inputs section of the Incompressible Flow window Figure 3 Fittings section of the In/compressible flow window Figure 4 Results section of the Calculation Type window Figure 5 Units Form Figure 6 Pipe Inner Diameter Calculator dialog Figure 7 Molecular Weight Calculator dialog Figure 8 Fittings Loss (K-value) Calculator dialog Figure 9 Pipe Roughness Calculator dialog Figure 10 PPDS Calculator dialog Figure 11 Selecting the Calculation type Figure 12 Inputs section of the Incompressible data Input window Figure 13 Fittings section of the Incompressible data Input window Figure 14 Results section of the Incompressible data Input window Figure 15 Graph of Pressure drop against Mass flow Figure 16 Summary Table Figure 17 Choosing a Fluid Flow Program Figure 18 Vertical Tank with a Dished and Conical End Figure 19 Inclined Vessel Appendices Appendix A In-cell Units Conversion Appendix B Choosing a Fluid Flow Program Appendix C Vessel Calibration PEW User Guide Page 5 of 86

6 Page 6 of 86 PEW User Guide

7 1. PEW User Guide 1.1. Introduction The Process Engineers Workbench (PEW) program processes individual process engineering calculations. It also allows the user to build up a collection (or project) of calculations which can then be used to generate summaries and graphs to analyse the results. All the calculations present at any one time, together with any summaries or graphs which have been created, comprise the project. Any combination of the various calculation types can be present in a project and several cases of the same type are allowed. A project can have any number of calculations, graphs and summaries each having its own subwindow that can be minimised or maximised Principle features of PEW Fluid flow calculations are for single, unbranched pipes of single diameter. Compressible flow calculations are available in isothermal and adiabatic modes and are valid up to approximately 0.3 Ma. Fluids must be single phase gas or liquid. PEW is capable of Design calculations as well as the usual Ratings calculations, that is, data about the piping system such as pipe inner diameter or roughness can be calculated from the fluid flowrate and pressure drop PEW Calculations The calculations contained in PEW are for: Fluid Flow Heat Transfer Mixing Equipment. These are described in the following sections: Fluid Flow The calculations available for Fluid Flow are: Incompressible Flow Compressible Flow Gravity Flow Manifold and Symmetrical T junctions Pressure Drop through Calculates either pressure drop, flowrate, roughness or diameter, given the other three, for flow of an incompressible fluid along a pipe of circular cross-section. Calculates any of inlet/outlet pressure, mass flowrate, or pipe diameter for adiabatic or isothermal flow of a compressible fluid along a circular cross-section pipe. Calculates either flowrate or depth of liquor in an inclined, partly filled pipe or duct or pipe diameter in an inclined pipe. Gives the pressure drop through various types of T-junction in round pipes. Both manifold flow and symmetrical flow are considered. Calculates both the perceived pressure drop (the static pressure PEW User Guide Page 7 of 86

8 Expansion/Contraction Orifice Calculation drop) and the frictional pressure loss for various types of expansion and contraction in cylindrical pipes. It displays the number of velocity heads lost in the fitting. This models an orifice or venturi required to measure the flowrate of a gas, liquid or steam. It can calculate any one of orifice diameter, pressure drop and flowrate given the two. The scope is limited to square-edged orifice plates with one of: Restrictor Orifice Two phase flow Corner pressure tappings D and D/2 pressure tappings Flange pressure tappings. This models the flow through restrictor orifices for either liquid or gas flows. It will calculate any one of flowrate, pressure drop and orifice diameter given the other two. This program is designed to evaluate the two phase flow regime in a pipe as well as the frictional and gravitational pressure drops and the void fraction Heat Transfer The calculations available for Heat Transfer are: It is based on the methods outlined in the HTFS handbook sheets TM1, 2, 4, 6, 12, 13, 14 and 15. Heat Transfer Coefficient Pipe Heat Loss Vessel Heat Loss The Heat Transfer Coefficient in Smooth Pipes is calculated. The pipe may be in any orientation and all flow types, from laminar to turbulent, are catered for. This calculates the heat loss from (or gain to) a lagged pipe. This models the heat loss from (or gain to) a flat-topped cylindrical storage vessel, partly full of liquid, standing on the ground, or raised above the ground. The vessel can be lagged or unlagged and the effect of solar radiation can be considered. Simple Heat Exchanger Tank Solar Heating The effect of wind speed, conduction into the ground (where appropriate) and conduction of heat between the liquid and vapour space are also modelled. This models the exit temperatures, the duty and log mean temperature difference for a heat exchanger from the inlet temperature, flowrates and specific heats, heat transfer area and overall coefficient. This models the incident solar radiation to flat-topped cylindrical tanks. It calculates the radiant heat at intervals throughout the day, the peak energy input and the total isolation during the day. Page 8 of 86 Allowance is made for the effects of latitude, time of year and cloud cover. PEW User Guide

9 Finned Tube Heat Transfer Batch Heating and Cooling Times This calculates the heat transfer coefficient and pressure drop for the flow of a gas over a bank of finned or plain tubes. This calculates either the time taken to heat (or cool) a batch to a target temperature or the temperature reached by a batch in a given time, given a particular heating/cooling load Mixing The calculations available for Mixing are: Vortex Profile Table of Power Numbers Speed versus Power Vortex Profile in unbaffled vessels calculates the shape of the vortex produced by agitator in a circular unbaffled vessel. It applies only to agitators mounted on a vertical shaft at the axis of the vessel. The shape is described by the heights of the liquid at the centre, agitator blade tip and circumference of the vessel. This is a pair of reference tables of power numbers for various configurations of agitators in baffled and unbaffled vessels under fully turbulent conditions. This calculation enables the evaluation of either agitator speed given the power or the power required by an agitator given the agitator speed Equipment The calculations available for Equipment are: The program uses fitted data from curves of Power Number as a function of Reynolds Number and applies correction factors for non-standard geometries. Vessel Calibration This calibrates cylindrical tanks that may have a flat, ellipsoidal, dished or conical ends independently of one another. Dished and conical ends may have a transition knuckle and the axis of the tank may be horizontal, vertical or inclined. PEW User Guide Page 9 of 86

10 1.3. How this guide is structured This guide is designed to assist the user in becoming quickly familiar with the capabilities of PEW, its interface and how the program is used. The chapters are organised as follows: Chapter 1 Chapter 2 Chapter 3 Appendices An introduction to PEW. Detailed information on the PEW user interface. A tutorial to guide the user through a typical PEW session emphasising the commonly used features. It is recommended that the user should read this chapter while running the program. Describe the In-cell units conversion feature, advice on choosing a Fluid Flow program and Vessel Calibration. Page 10 of 86 PEW User Guide

11 2. The PEW User Interface The user interface displays menus and a toolbar that allows the system being modelled to be easily defined. It also offers many useful features including automatic units conversion and a calculator. As a general concept, the PEW interface for a calculation consists of an input section on the left of the screen and a results section on the right. The layout is designed to allow both the inputs and results to be displayed on a single screen and to be printed on a single sheet of A4 paper. On-line help is available within the program The PEW start up screen The PEW start up screen consists of the following: Menus Bar Toolbar Buttons Status Bar Calculation Type selection dialog Displays the menu options that are available. Descriptive text appears automatically as the cursor is held over the buttons to describe their function. Displays the upper and lower limits of the information that can be entered when the cursor is placed in an input cell. The first action to take when the PEW start up screen appears is to select the type of calculation to work on (see section 2.2 for more information). Figure 1 PEW start up screen The following sections in this chapter contain detailed information on how this interface is used. PEW User Guide Page 11 of 86

12 2.2. Calculation Type Inputs Forms The first step when using PEW is to select the type of calculation to work on. The calculation types are accessed by selecting Add from the Calculation menu or clicking the Add a new case button (see left) on the toolbar. The Calculation types available are: Fluid flow Heat transfer Mixing Equipment. The selections available from these Calculation types are: Fluid flow Incompressible Compressible Gravity flow Manifold T-junction Symmetrical T-junction Expansion/contraction Orifice Restrictor Two phase flow. Heat transfer Heat transfer coefficients Pipe heat loss Vessel heat loss Batch heating/cooling Simple heat exchanger Tank solar heating Finned tube. Mixing Vortex profile Power numbers Speed/power curves. Equipment Vessel calibration. Selecting a calculation type brings up the appropriate form for that calculation. The form includes both the input data and results for that calculation. The details of the input portion of the forms are described further in this chapter. Page 12 of 86 PEW User Guide

13 The example Input form shown in Figure 2 appears when Fluid flow and Incompressible are selected. Clicking the Edit... button toggles between the Inputs section at the top of the Incompressible Flow window and the Fittings section at the bottom of the window. Figure 2 Inputs section of the Incompressible Flow window Note. Although the units are displayed in metric, the values can be entered in any units see Appendix A for more information. The default units can be changed from metric to any other required unit set see section for more information. The inputs forms are always populated with reasonable default values as a guide to the type of information required. Clicking an input cell displays (on the status bar at the bottom of the screen) the upper and lower limits of the information that can be entered. PEW User Guide Page 13 of 86

14 Fluid Flow Inputs The following are the different types of calculation available for Fluid Flow: Incompressible Compressible Gravity Flow Manifold T-junction Symmetrical T-junction Expansion/Contraction Orifice Restrictor Two Phase Flow Incompressible Calculates the incompressible flow along a single, unbranched, cylindrical pipe of a fixed diameter. The following selections can be made: Calculate Pipework Losses Select Calculate from one of the following: Flow Diameter Roughness Pressure Drop (default selection). Values for the other three must be supplied and the text (estimated) appears next to the value which is to be calculated. Enter values for: Length The actual length of the pipe. Diameter The internal pipe diameter (see section for more information). Lining thickness If there is a lining to the pipe, enter that here. Roughness The absolute roughness in the pipe. The value depends on the material of construction and condition of the pipe (see section for more information). Enter values for: Static head loss This is the difference in elevation between the point of discharge and the point of entry to the pipe. Therefore, this number is positive if the pipe runs uphill and negative if it runs downhill. Fittings loss (velocity heads) This is the total K-value for the pipe and should take into account pipe entry and exit effects, fittings losses, bends, Tee's etc. The Edit button displays a form which describes the pipe fittings which comprise the fittings loss. Page 14 of 86 PEW User Guide

15 Fluid Properties Process Conditions Enter values for: Density The actual density of the fluid at operating conditions. Viscosity The actual viscosity of the fluid at operating conditions. Enter values for: Pressure drop (estimated) The measured or estimated pressure drop down the pipe is needed. The program does not cater for reverse flow conditions so the pressure drop must not be less than the static head loss. If this data is real, there may be plant data errors (static head errors ), instrument errors or gas entrainment. Mass flow The flowrate down the pipe (default value is kg/s) Compressible Calculates the compressible flow along a single, unbranched, cylindrical pipe of a fixed diameter. The following selections can be made: Flow mode Calculate Pipework Select Flow mode from either: Isothermal The isothermal theory is most suitable when pressure and velocity changes along the pipe are small relative to the pressure and velocity of the fluid. Adiabatic For higher Mach numbers, adiabatic theory is normally preferred as smaller errors are likely than for other conditions. Select Calculate from one of the following: Flow Diameter Inlet Pressure Outlet Pressure (this is the default selection). Values for the other three must be supplied and the text (estimated) appears next to the value which is to be calculated. Enter values for: Length The actual length of the pipe. Diameter The internal pipe diameter (see section for more information). Lining thickness The pipe lining thickness (if applicable). Roughness The absolute roughness in the pipe. The value depends on the material of construction and condition of the pipe (see section for more information). Fittings loss (velocity heads) PEW User Guide Page 15 of 86

16 This is the total K-value for the pipe and should take into account pipe entry and exit effects, fittings losses, bends, Tee's etc. The Edit button displays a form which describes the pipe fittings which comprise the fittings loss. Fluid properties Process conditions Enter values for: Density at 0 C and 1 bara The density should be given at C and 1 bara as the calculation uses ideal gas theory to calculate the densities at operating conditions from this value. Viscosity (process conditions) The viscosity at mean operating conditions is needed. This implies that some idea of the answers is needed before running the program. For example, the viscosity of steam is approximately 0.02 cp. Gamma The ratio of specific heats, gamma or Cp/Cv is required for any compressible flow calculations. Enter values for: Inlet / Outlet pressure Either the measured or the target value is required for each of these. The program will reject the input if the outlet pressure is greater than the inlet pressure. Inlet temperature The inlet temperature is needed to calculate the actual density and, for adiabatic flow, the temperature loss. Mass flow The mass flowrate down the pipe is required. A volume flowrate cannot be used as any of the conditions inputs could affect the actual mass flowrate. Page 16 of 86 PEW User Guide

17 Gravity Flow Calculates the gravity flow in an inclined, partially filled pipe or duct. The following selections can be made: Container type Calculate Dimensions Fluid properties Pipe conditions Select Container type from either: Pipe (a closed vessel) Duct (an open vessel). Select Calculate from one of the following: Flowrate The mass flowrate in the container. Depth The depth of the fluid in the container. Diameter (pipe only) The diameter of the pipe. Enter values for: Lining thickness Enter a value of 0.0 if the pipe or duct is unlined or the lining thickness has been included in the diameter. A typical epoxy or ebonite lining has a thickness of 6 mm. Roughness of wall The absolute roughness in the pipe and the condition of the pipe. Slope A positive fraction is required. A slope of (1:40) is recommended as any larger will lead to wave formation. Smaller slopes are more difficult to install though slopes of (1:200) are commonly found in chlorine cellroom headers. Enter values for: Density and Viscosity of the fluid at operating conditions. Different inputs are required depending on the calculated variable and whether the container is a pipe or a duct. The required inputs are: Container Type Calculated Variable Pipe Duct Flowrate Depth Pipe Diameter Relative Depth Pipe Diameter Liquor Flowrate Duct Width Liquor Level Duct Width Liquor Flowrate Diameter Maximum Relative Depth Liquor Flowrate N/A PEW User Guide Page 17 of 86

18 When the container is a Pipe: Calculate Flowrate This is the mass flowrate. The following inputs are required: Pipe Diameter This is the actual inner diameter as the lining thickness is subtracted if the lining is present. Relative Depth The observed relative diameter is required, that is, the observed depth of liquid/pipe diameter. Calculate Depth The observed relative diameter is required, that is, the observed depth of liquid/pipe diameter. Values above 0.8 can mean that the maximum stable flow limitation is being reached. The following inputs are required: Pipe Diameter This is the actual inner diameter as the lining thickness is subtracted if the lining is present. Liquor Flowrate The actual mass flowrate. Calculate Diameter The program calculates internal diameters for pipes assuming it to be an ANSI 150 standard carbon steel pipe as follows: 1 1+ in Schedule in Schedule in Schedule in Schedule Wall 20, 24 in Schedule 80 Above 24 in Metric sizes. The result will be the actual inner diameter seen by the flowing liquor as the lining thickness is subtracted if the lining is present. The following inputs are required. Maximum Relative Depth The maximum relative depth allowable before a larger pipe size is required. Values above 0.8 can mean that the maximum stable flow limitation is being reached. Liquor Flowrate The actual mass flowrate. When the container is a Duct: Calculate Flowrate This is the mass flowrate. The following inputs are required: Duct Width The duct width. The program subtracts the lining thickness if one has been specified. Liquor Level The fluid level in the duct. Page 18 of 86 PEW User Guide

19 Calculate Depth This is the fluid level in the duct. The following inputs are required: Duct Width The duct width. The program subtracts the lining thickness if one has been specified. Liquor Flowrate The actual mass flowrate Manifold T-junction Calculates the pressure drop for a T-junction consisting of a straight manifold of consistent bore with a (smaller) branch pipe at right angles to it. Both combining and dividing flows are possible. The following selections can be made: Flow Pipework Fluid properties Select Flow type from one of the following: Combining Dividing. Enter values for: Mass flow into/out of manifold The mass flow into the T along the manifold and the mass flow away from the T along the manifold are required. Mass flow in branch PEW calculates the branch flow from the mass flow into the manifold and the mass flow out of the manifold. If the two known flowrates include the branch flow, the calculator can be used to calculate the missing manifold flow. Enter values for: Manifold diameter This is the diameter of the main pipe. Note this is assumed to be straight with the branch at right angles. Branch diameter This is the diameter of the branch. This must not be greater than the manifold diameter. The branch-manifold join is assumed to be sharp-edged with no rounding Enter values for: Density manifold in/out The density of the fluid in the inlet and outlet manifolds should be supplied at the operating conditions. Density in branch The density of the fluid in the branch at the operating conditions is also required. Note. These correlations are for single phase flow only. Viscosity This is only required to check the Reynolds Number. If in doubt, make it too large rather than too small. PEW User Guide Page 19 of 86

20 Symmetrical T-junction Calculates the pressure drop in T-junctions consisting of a straight manifold of constant bore with a branch pipe of the same bore at right angles to it. The junction should have a sharp-edged join with all the flow entering or leaving via the branch. They are of two types of T-junction: Combining or Dividing. Flow is symmetrical about the branch either entering or leaving through both arms of the T. The following selections can be made: Flows Pipe diameters Fluid properties Select Flows from one of the following: Combining Dividing. The T-junction is symmetrical so the branch and the main part of the T-junction are assumed to have the same diameter. Enter values for: Inlet / Outlet density The density of the inlet and outlet fluid should be given at the operating conditions. Note. These correlations are for single phase flow only. Viscosity This is only required to check the Reynolds Number. If in doubt, make it too large rather than too small Expansion/Contraction Calculates both the perceived pressure drop (the static pressure drop) and the frictional pressure loss for various types of expansion and contraction in cylindrical pipes. The following selections can be made: Pipe diameter Included angle of expansion Enter Pipe diameter values for: Inlet The diameter of the upstream pipe. Outlet The diameter of the downstream pipe. PEW compares the two diameters to determine whether a contraction or expansion is being specified and sets the shape options for the fitting accordingly. Specify the following if an expansion is detected: Conical Expansion types Data is available for various angles of the cone. These are: 0 to to to to to 120 Page 20 of 86 PEW User Guide

21 Abrupt Expansion types An immediate right-angle (180) change in diameter. Contraction type If a contraction is detected, specify the following: Rounded A smoothly rounded change in diameter. Tapered Data used here assumes a cone of total angle 60 degrees. Abrupt An immediate right angle change in diameter. Process conditions Enter values for: Mass flow The mass flow through the fitting. Inlet density The inlet density of the fluid in the pipe at the entry to the fitting. Outlet density The outlet density of the fluid in the pipe at the exit from the fitting. Viscosity This is only required to check the Reynolds Number. If in doubt, make it too large rather than too small. PEW User Guide Page 21 of 86

22 Orifice Models an orifice or venturi required to measure the flowrate of a gas, liquid or steam. It can calculate one of orifice diameter, pressure drop and flowrate given the other two. The scope is limited to square-edged orifice plates with one of the following: Corner pressure tapping D and D/2 pressure tappings Flange pressure tappings. The following selections can be made: General data Select the variable to calculate from one of the following: Flow Pressure drop Orifice diameter. Select the Fluid from the following: Liquid Gas Steam. The remaining information required in the General Data section is dependant on the choices made for the Fluid and the required variable to Calculate. The required inputs are: Fluid Type Calculated Variable Liquid Gas Steam Flow Density Density Gamma Gamma Pressure Drop Density Flow Meter Range Density Gamma Flow Meter Range Gamma Flow Meter Range Orifice Diameter Density Flow Meter Range Density Gamma Flow Meter Range Gamma Flow Meter Range The various inputs are: Density Give a reference fluid density at 20 C and 1 atmosphere. Gamma The ratio of specific heats is required for gas or steam typically around 1.4. Page 22 of 86 PEW User Guide

23 Upstream physical properties Orifice details Flow Meter Range The maximum flow allowed on the flow meter is required, unless this is the calculated variable. If a pre-existing orifice plate is being rated, it is the flow that is used to calculate the pressure drop. Enter values for: Pressure The pressure upstream of the orifice plate. Temperature The temperature upstream of the orifice. Density The density upstream of the orifice. Viscosity The viscosity upstream of the orifice. The calculated variable chosen earlier determines the values to be entered here: Calculated variable Flow Inputs are required for: Orifice diameter Orifice pressure drop Calculated variable Pressure Drop Inputs are required for: Orifice diameter Calculated variable Orifice diameter Inputs are required for: Standard Orifice (Y/N) If a standard orifice size is to be found, the program assumes the given maximum flow and uses the closest pressure drop to that given. Orifice pressure drop Class B (Y/N) Is a class B calculation required? If No then the pipe condition and a % correction must be supplied. The Pipe category should be selected from one of the following: 1. Steel non-rusty cold-drawn 2. Steel non-rusty seamless 3. Steel non-rusty welded 4. Steel slightly rusty 5. Steel rusty 6. Steel slightly over-rusted 7. Steel new bitumenised 8. Steel used bitumenised 9. Steel galvanised 10. Cast iron non-rusty 11. Cast iron rusty 12. Cast iron bitumenised. PEW User Guide Page 23 of 86

24 Correction Factor The percentage of pressure drop for expansibility, Re and correction factors. Typical value is 50%. Select Taps from one of the following: Corner D and D/2 Flanged Venturi Tolerances This is only appropriate when the upstream and downstream straight pipe lengths are less than the minimum. Leave as zero unless there is a special reason. Corrections Leave as zero unless there is a special reason. Material Select the pipe Material from one of the following: MS (Mild Steel) SS (Stainless Steel) CI (Cast Iron) Other (any other). Pipe internal diameter Enter the actual internal diameter of the pipe Restrictor This program models the flow through restrictor orifices for either liquid or gas flows. It calculates any one of flowrate, pressure drop and orifice diameter given the other two. The following selections can be made: Calculate Geometry Select Calculate from one of the following: Flow Pressure drop Orifice diameter For gases: this should be less than 13% of the pipe area. If it is much greater than this, the experimental results on which the calculations are based do not apply and theoretical extrapolation may be suspect. For liquids: the relevant ratio is Orifice thickness/diameter (t/d). If this is between 0.6 and 1.0 it is not possible to predict whether the flow reattaches before leaving the orifice, and this affects the pressure drop. The calculation assumes 0.8 as the dividing line but displays a warning. Enter values for: Pipe diameter The internal diameter of the pipe must be given. For gases, the ratio of orifice diameter to this diameter is important. Page 24 of 86 PEW User Guide

25 Orifice diameter For gases: This should be less than 13% of the pipe area. If it is much greater than this, the experimental results on which the calculations are based do not apply and theoretical extrapolation may be suspect. For liquids: The relevant ratio is Orifice thickness/diameter (t/d). If this is between 0.6 and 1.0 it is not possible to predict whether the flow reattaches before leaving the orifice, and this affects the pressure drop. The calculation assumes 0.8 as the dividing line, but gives a warning. For calculating orifice diameter, the program first assumes separated flow and, if this indicates uncertainty, calculates for reattached flow. If the answer is still in the uncertain region then both values are given together with a warning. Plate thickness This is the thickness from the upstream to the downstream side. It is important for liquid flow (see above). Process conditions Fluid properties Enter values for: Upstream/Downstream pressure If the pressure drop calculation is requested, the downstream pressure is calculated from the upstream pressure. For gases, the downstream pressure should not be less than one fifth of the upstream pressure. Mass flow The mass flowrate can be supplied or calculated from orifice diameter and pressure drop if required. Upstream temperature The upstream temperature must be supplied but the program will calculate the static and stagnation temperatures. Enter the following values for either Liquid or Gas: Liquid: Viscosity Fluid viscosity. Typical values are around 1 cp for liquids. Density Density. An example is Water = 1000 kg/m3. Gas: Viscosity Fluid viscosity. Typical values are around cp for air at ambient conditions. Compressibility The Compressibility factor. This represents the deviation from ideal. Exponent K This is the exponent of isentropic expansion, for ideal gases this is the same as Gamma. PEW User Guide Page 25 of 86

26 Molecular weight See section for more information on the molecular weight calculator. Results The results are displayed on screen when the problem is calculated. If the calculation generates any warnings or errors, these can be accessed by pressing the Show details button. A warning message indicating that more information is available appears in red Two Phase Flow This program characterises the two phase flow regime using several different methods. The frictional and gravitational pressure gradients and the calculated void fraction are also supplied. The following selections can be made: Pipe characteristics Process fluids Enter the following values: Slope of pipe The angle of the pipe to the horizontal is required with negative being defined as down flow. The program has no facility to handle angled pipes. Therefore, it performs the calculation for both horizontal and vertical flow then reports the results for both. Pipe diameter The internal pipe diameter. Pipe roughness See section for more information on the Pipe Roughness Calculator. Enter the following values for either Liquid or Vapour: Liquid: Flowrate (required in mass units). Density (at the operating conditions). Typical values are: Water: 1000 kg/m 3 Ethanol: 789 kg/m 3 Acetone: 788 kg/m 3 Viscosity (at the operating conditions). Typical values are: Water: Cp Ethanol: Cp Benzene: 64.7 Cp. Liquid Surface Tension (Mandatory) Typical surface tension values are: Water: 72 dyn/cm Methanol: 26 dyn/cm Benzene: 28 dyn/cm Mercury: 472 dyn/cm Page 26 of 86 PEW User Guide

27 Vapour: Flowrate (required in mass units). Density (at the operating conditions). Typical values are: Air: kg/m 3 CO2: kg/m 3 Ethane: kg/m 3 Viscosity (at the operating conditions). Typical values are: Air: Cp Ethanol: Cp Benzene: Cp. PEW User Guide Page 27 of 86

28 Heat Transfer Inputs This program calculates coefficients for smooth pipes. The pipe can be in any orientation and all the different flow regimes from laminar to turbulent are catered for. The following are the different types of calculation available for Heat Transfer: Heat Transfer Coefficients Pipe Heat Loss Vessel Heat Loss Batch Heating/Cooling Simple Heat Exchanger Tank Solar Heating Finned Tube Heat Transfer Coefficients The following selections can be made: Flowrates Pipe properties System Temperatures Select Flowrates from one of the following: Velocity (in m/s) Enter the mean velocity in the pipe. Mass (in kg/s) Enter the mass flowrate in the pipe. Volume (in m 3 /s) Enter the volume flowrate in the pipe. Enter values for: Diameter (Internal) This is assumed to be a smooth pipe, that is, a relative roughness of below Length (from inlet) The length of the tube from the inlet. Orientation Enter whether the pipe is horizontal or vertical. Flow direction The direction of flow in a vertical pipe is required. Enter values for: Wall temperature The temperature of the wall. If it is not known then it can be found using an estimation of the tube side coefficient, the wall resistance and the temperature and heat transfer coefficient of the fluid outside the tube. Fluid inlet temperature The temperature of the bulk fluid at the inlet is required. Fluid outlet temperature The outlet temperature of the bulk fluid is required. Page 28 of 86 PEW User Guide

29 Fluid Physical Properties Enter the following values for either Liquid or Gas: Viscosity (Fluid Temp) Some typical values are (cp ): 25 C 100 C Water Hydrocarbons ( liquid ) Hydrocarbons ( vapours ) Steam Air Viscosity (Wall Temp) Some typical values are (cp ): 25 C 100 C Water Hydrocarbons ( liquid ) Hydrocarbons ( vapours ) Steam Air Density The density at the bulk fluid temperature is required for horizontal tubes and at the wall temperature for vertical tubes. Specific Heat Capacity The specific heat capacity at the bulk fluid temperature is required. Some typical values are ( all J/kg.K ): Water 4200 Hydrocarbons (gaseous and liquid) Steam 2000 Air 1000 Thermal Conductivity The thermal conductivity is required at the bulk fluid temperature. Some typical values are ( all W/m.K ): 25 C 100 C Water Hydrocarbons (liquid) Hydrocarbons (vapours) Steam Air Thermal Expansion Coefficient The thermal expansion coefficient at the bulk fluid temperature is required for horizontal tubes and at the wall temperature for vertical tubes. The thermal expansion coefficient may be estimated using the difference in densities at two temperatures or set to 1/T(K) for gases at low pressures. PEW User Guide Page 29 of 86

30 Pipe Heat Loss Calculates the heat loss (or gain) from a (lagged) pipe either at a single point or as a profile along the pipe. The following selections can be made: Calculation type Geometry Process Select Calculation type from one of the following: Single point Profile along pipe. Enter values for: Pipe length This is not used by the calculation program itself as it displays the heat loss per metre of pipe. However, when that is returned to PEW, the total heat loss is calculated using this length. This assumes constant fluid temperature down the pipe. Internal diameter This diameter excludes any lining which may be present. Wall thickness The thickness of the wall should be given excluding any lagging or lining. Lagging thickness This can be zero if no lagging is present. Lining thickness The lining is assumed to be within the pipe. If no lining is present then enter zero for this value. The lining thickness is limited to 90% of the pipe radius as it is assumed that at least 10% of the pipe should remain clear. Select Fluid from either of the following: Condensing If the fluid is condensing then it is assumed to be at a constant temperature along the length of the pipe and the temperature profile option is not be displayed. Non-condensing Enter values for: Mass Flow The mass flowrate of fluid through the pipe helps to determine the inside heat transfer coefficient. Note that the underlying calculation engine assumes turbulent flow in its calculations. Internal temperature This is the average temperature of the fluid within the pipe. External Temperature The temperature of the air outside the pipe must lie between -40 C and 40 C as the properties of air in the program only cover this range. Page 30 of 86 PEW User Guide

31 Heat transfer Select Inside coefficient from either of the following: Given Calculated Enter values for: Wall Conductivity (the thermal conductivity of the wall material). Some approximate values in W/m. C are: Brick Hastelloy 9-20 Inconel Stainless Monel c.25 Carbon Steel Lagging conductivity Some typical values (W/m. C) are: Nilflame 100 C Calcium Silicate 100 C 600 C Lining conductivity Typical values (W/m. C) are: Plastic >1.7 Glass 1 -> 4 Inside dirt resistance This must lie between 0 and 0.05 Surface emissivity This determines the heat loss due to radiation. The background temperature is assumed to be the air temperature. A figure of 0.9 represents a typically dirty surface. Inside coefficient This is the heat transfer coefficient between the fluid in the pipe and the pipe wall. This can be calculated by the program if it is not supplied. The program calculates the inside coefficient given fluid flow, viscosity and thermal conductivity but turbulent flow is assumed. If laminar flow is suspected, the coefficient must be estimated and supplied to the program. Additionally, if the tube contains a vapour which is condensing due to the heat loss, the coefficient is much higher than the calculated single phase values. Note that condensation can occur on the pipe walls even if the bulk vapour is superheated (wet wall superheated). For cases other than single phase turbulent flow the user should calculate the inside coefficient and input it into the program. In the absence of a user specified value, the program assumes an inside coefficient of 10,000 w/m 2 for condensing fluids. PEW User Guide Page 31 of 86

32 Fluid properties Results Properties for the fluid must be supplied at two temperatures if a temperature profile is to be calculated. Enter values for: Temperatures Specific heat capacity Typical specific heats (J/kg. C) are: Water approx Steam Organic liquids Viscosity Typical viscosities (cp) are: Water Steam approx Conductivity Typical conductivities (j/kg.c) are: Water approx. 0.6 Steam Basic results are shown on screen in the form of heat loss in W or W/m versus differing wind speeds. More detailed results are available by accessing the Show details button. For a single point calculation these include for each wind speed: The temperatures at the interface between fluid, lining, wall, lagging and air. The inside heat transfer coefficient and the elements which comprise the outside heat transfer coefficient. Natural convection forced, forced convection and radiation. For a temperature profile case, these values are given at 10 equidistant points along the pipe in addition to the inlet. Page 32 of 86 PEW User Guide

33 Vessel Heat Loss This program models the heat loss from a flat-tipped cylindrical storage vessel partly filled with liquid, standing on the ground or raised on legs. The vessel can be lagged or unlagged and the effects of solar radiation can be considered. The effects of windspeed, conduction into the ground (where appropriate) and conduction of heat between the liquid and vapour space within the vessel can also modelled. The following selections can be made: Tank description The tank is assumed to be a vertical cylinder with a flat roof. Enter the following Tank description information Internal diameter The internal diameter. Height The height of the tank. Wall thickness The thickness of the tank walls. The roof is assumed to be the same thickness. Liquid level % The liquid level in the tank as a percentage. Temperature The temperature of the liquid in the tank. The vapour temperature is calculated and so is closer to the ambient temperature than the liquid. Pressure The pressure within the tank. Conductivity The thermal conductivity of the tank. Some typical approximate values in W/m.C are: Brick Hastelloy 9-20 Inconel Stainless Monel 25 (approx.) Carbon Steel Location Select either On Ground or On Legs. For a tank on legs, the calculation assumes that the vessel is completely surrounded by air at constant ambient conditions and the base is assumed to be flat. See the following section Ground conditions for more information. PEW User Guide Page 33 of 86

34 Lagging Emissivities Solar radiation Any combination of walls, roof and base of the tank can be lagged. However, it is assumed that the base of a tank on the ground cannot be lagged. Select Lagging from one of the following: Walls Roof Base Specify the following if any lagging is present: Thickness All the lagging is assumed to be the same thickness. Thermal Conductivity The lagging thermal conductivity. Typical values are: Nilflame 100 C Calcium Sulphate 100 C Enter a value for: 600 C Tank The tank emissivity is required if any tank surface is unlagged. A typical value is 0.9 (This is the tank surface not the lagging surface). Lagging The lagging emissivity is required if any lagging is present. A typical value is 0.8. The calculations can be carried out with or without including the heating effect of the sun on the tank. The effects are assumed to apply over the entire vessel top and over the projected area of half of the wetted and unwetted cylinder. Enter either Yes or No: Yes: The program iterates to achieve a balance between heat lost/gained by the liquid surface, heat lost/gained by the unwetted walls in the sun and in the shade, and the heat lost/gained by the roof in the sun. If solar radiation is to be considered, the following information is required: Latitude The latitude (in degrees) north of the equator is needed. A value of 50 would be typical for the UK. Solar Energy The solar energy incident on a horizontal surface. Values can be calculated for a given set of conditions using the tank solar heating program in PEW. No: Solar radiation is ignored. Page 34 of 86 PEW User Guide

35 Ambient conditions Ground conditions Physical Properties Liquid in tank Vapour in tank Enter Ambient conditions values for: Temperature The ambient temperature outside the tank should be supplied. It is assumed to be constant all around the tank. Wind Speed The wind speed affects the convection from the tank surfaces. Typical values are: Gale force 3 to 4 = 5 m/s Gale force 8 = 15 m/s. If the tank location is selected as On Ground, enter values for: Temperature The ground on which the tank sits is modelled as an infinite flat solid and heat loss into it is through conduction. Thermal conductivity Typical values are around 0.5 W/m2.C Physical properties for both the liquid and vapour are required. The physical properties of the tank liquid at three reference temperatures are required. The first two reference temperatures should span the range of temperatures in the tank and surroundings and are the temperatures for the following data on density, conductivity and specific heat. The third reference temperature is only needed to calculate liquid viscosity which is modelled with an Antoine type equation. The default property values provided are those of water. Density Liquid density at the first two reference temperatures. Note the second density value must be less than the first, because otherwise the coefficient of volumetric expansion will be negative, and the Grashof number, used in the correlations for htc becomes negative, with strange effects. Conductivity Liquid thermal conductivities at the first two reference temperatures. Specific heat Liquid specific heat at the first two reference temperatures. Viscosity Liquid viscosity at three temperatures. These must not be identical or the program will not be able to work out the constants for the Antoine-like equation that it uses. The physical properties of the tank vapour at two reference temperatures are required. The reference temperatures should span the range of temperatures in the tank and surroundings. Is the vapour air? Enter either Yes or No: Yes: PEW User Guide Page 35 of 86

36 The program has built in correlations for the physical properties of air so vapour properties for air are not required. The default property values provided are those of air but do not give exactly the same answers as the internal correlations, as these are more accurate. No: The following values must be supplied if the vapour is not air: Vapour thermal conductivity at the first two reference temperatures. Vapour specific heat at the first two reference temperatures. Vapour viscosity at the first two reference temperatures. Vapour molecular weight. The average molecular weight at operating conditions. Results The total heat loss for the vessel appears on the screen. More detailed results are available by pressing the Show details button Batch Heating/Cooling This program calculates either the time taken to heat (or cool) a batch to a target temperature or the temperature reached by a batch in a given time given a heating/cooling load. In either case, PEW divides the target to 10 equal time/temperature points to indicate the progress of the batch to its final state. The following selections can be made: Operating Conditions Select Calculate from one of the following: Duration The time required to heat up or cool down the batch. Final Temperature The final temperature of the batch is calculated given the time available. Select Heating Medium from one of the following: Non-Isothermal The heat exchange medium is assumed to have a constant Cp, and so cools down through the jacket/heat exchanger. Isothermal The heat exchange medium is assumed to be at a constant temperature. For example, condensing steam or evaporating refrigerant. The remaining values required for the operating conditions section are: Batch start temperature The temperature of the batch at the start of the time period being considered. Inlet temperature of the HE medium This is the temperature of the heating/cooling medium as it enters the coils/jacket/exchanger. For the isothermal case, this is its temperature throughout the coils/jacket/exchanger. Page 36 of 86 PEW User Guide

37 and either: OR: Final Temperature of Batch This is the target temperature of the batch. PEW divides the progression towards this into ten equal increments to show how the temperature varies during the heating/cooling period. Duration of Heating The time for which heating or cooling is occurring. The program divides this into ten equal intervals to display the temperature of the batch as a function of time. Vessel Data Heat Exchange Data Supplementary Data Select the Type of Vessel from one of the following: OR: Jacketed Heat exchange occurs within the vessel the batch is assumed perfectly mixed with any deviations from this being accommodated by changes in U. External HE The batch is constantly pumped out of the vessel and through an external heat exchanger. The user must supply the flowrate of the batch through this external exchanger (assumed to be countercurrent). Additional vessel data required is: Mass of batch The total mass of the batch. This should include the mass of anything to be heated/ cooled simultaneously the vessel for example. Specific Heat of Batch The specific heat (not a function of temperature) of the batch. This must take account of the effect of including the vessel etc. in the batch mass to be heated. Enter values for: Heat Transfer Area This is the effective area for heat exchange given the U assumed. Overall Heat Transfer Coefficient (HTC) The U value for the vessels jacket/coils or the external HE. Enter values for: Flow of Batch through HE This is only required when you have specified an external heat exchanger and is the rate at which the batch liquid is pumped through that exchanger. Flowrate of HE medium The flow of the heat exchange medium through the jacket/coils/exchanger. This is only required when a nonisothermal heating/cooling medium is specified. PEW User Guide Page 37 of 86

38 Specific heat of HE medium The specific heat of the heat exchange medium. This is only required when a non-isothermal heating/cooling medium is specified Simple Heat Exchanger This program models the exit temperatures, the duty and the log mean temperature difference for a heat exchanger given the inlet temperatures, flowrates and specified heats, heat transfer area and overall coefficient. The following selections can be made: Hot/Cold stream inlet temperature Hot/Cold stream thermal flow UA value Flow arrangement Enter values for the inlet temperatures of the streams to the exchanger for both hot and cold streams these being defined as: Hot stream The stream to be cooled down. Cold stream The stream to be heated up. Enter values for thermal flows of the hot and cold streams. These can be calculated for each stream by multiplying the flowrate of the stream by the average heat capacity of the stream. This is the product of the overall heat transfer coefficient and the heat exchanged area. The pipes in the heat exchanger can be arranged as either: counter current co-current a mixed arrangement of both Tank Solar Heating This program calculates the incident solar radiation to flat-topped cylindrical tanks. It calculates the radiant heat at intervals throughout the day, the peak energy input and the total insolation during the day. Allowance is made for the effects of latitude, time of year and cloud cover. The following selections can be made: Month/Day of the month Latitude Tank diameter Tank height As the amount of solar radiation varies through the year, the date for the calculation must be specified. as Month and Day of the month. The default values are the current date. Enter a value for the latitude of the tank's position. Enter a negative value to indicate the southern hemisphere. A typical value for mid-england is 55. Enter a value for the Tank diameter. Enter a value for the Tank height. Page 38 of 86 PEW User Guide

39 Coefficient of air transparency Cloudiness factor Typical values of the air transparency vary between 0.7 and If in doubt use a value of 0.8. The Cloudiness factor varies from 1.0 for a cloudless day to 0.7 for heavy cloud Finned Tube This program calculates the outside film coefficient and pressure drop for fluid flowing over a rectangular bank or plain or finned tubes. The tubes in successive rows can be either in-line or staggered. The following selections can be made: Tube type Layout Tubes Mandatory. Select from either: Plain Low fin High fin. Select for either: Inline Staggered Equatorial. Enter values for: Note. Lateral spacing This is the distance between centres of tubes in the same tube row. Row spacing This is the perpendicular distance between centres of tubes in adjacent rows. This is not needed for equilateral layouts. Length The length of the tubes. Tubes per row Enter the number of tubes in each row. No of rows Enter the number of tube rows. Roughness Enter the roughness of the tube surface. This is only needed for plain tubes. Base tube diameter The outside diameter of the tube. The Roughness field is not available when Low or High fin have been selected for Tube type. PEW User Guide Page 39 of 86

40 Fins Fluid This part of the form is only available when Low or High fin have been selected for Tube type. Enter values for: Height Enter the height of the fins on the tube. For Lowfin tubes the maximum height is 6.35mm and for highfin tubes the maximum is 50mm. Thickness Enter the thickness of the fins on the tube. Thermal conductivity Enter a value for the thermal conductivity of the fins. This is not required for plain tubes. Select one of the following: Fin pitch This is the distance between the centre lines of successive fins. It is the reciprocal of Fins/m. Fin gap Fin gap, or fin spacing is defined as the distance between the inside faces of neighbouring fins. Fins per metre Enter the number of fins per metre of tube length. Enter values for: Flowrate The flowrate of the gas over the bank of tubes. Viscosity Enter the viscosity of the gas flowing over the tube bank. Thermal conductivity Enter the thermal conductivity of the gas flowing over the tube bank. Specific heat Enter the specific heat of the gas flowing over the tube bank. Density Enter the density of the gas flowing over the tube bank. Page 40 of 86 PEW User Guide

41 Mixing Inputs The following are the different types of calculation available for Mixing: Vortex Profile Power Numbers Speed/Power curves Vortex Profile This program calculates the shape of the vortex produced by an agitator in a circular unbaffled tank. It applies only to agitators mounted on a vertical shaft at the axis of the vessel. The shape is described by the heights of the liquid at the centre, agitated blade tip and circumference of the vessel. The following selections can be made: Vessel Diameter Agitator Diameter Agitator Speed Batch Static Height Batch Static Height dc/d Agitator Blade Width This is the inside diameter of the stirred vessel. The calculation only applies to unbaffled vessels. This is the overall diameter of the agitator blades. The agitator speed is used to calculate the angular velocity of the batch both in the forced vortex core and in the free vortex which surrounds it. It is these vortices that cause the depression of the free surface. This is the total depth of liquid in the vessel with the agitator not running. It is not currently used in the calculation, but is included so that its relation to the calculated differences can be easily seen. This is the total depth of liquid in the vessel with the agitator not running. It is not currently used in the calculation but is included so that its relation to the calculated differences can be easily seen. The forced vortex is that part of the batch which rotates at the same angular velocity as the agitator itself. The size of the forced vortex determines the overall shape of the free surface. dc/d is the ratio of the forced vortex diameter (dc) to the agitator diameter (D). This option should be used for disc turbines with the default value of Use a value of 0.73 if in doubt over other types. OR: This is the width of the agitator measured in a plane parallel to the agitator shaft. It is not the actual blade width if the blades are inclined. This is used to estimate the forced vortex core size using a correlation which is only valid for flat paddles. Use the dc/d option if in doubt. PEW User Guide Page 41 of 86

42 Power Numbers This is a pair of reference tables of power numbers for various configurations of agitators in baffled and partially baffled tanks under fully turbulent conditions. A pair of options toggles between the tables for baffled and partially baffled data Speed/Power curves This program enables the evaluation of either agitator speed given the power input or the power required by an agitator given the agitator speed. The program uses fitted data from curves of Power Number as a function of Reynolds Number and applies correction factors for non-standard geometries. The following selections can be made: Give General This determines the calculation type. Select one of the following: Speed The speed and geometry need to be defined and the program calculates agitator power. Power or Power/Vol The power requirement is given either as power or power per unit volume together with the geometry. The program calculates agitator power. Select one of the following (this is dependent on which option was chosen above in Give): OR: Speed The rotational speed of the shaft on which the impeller(s) is/are mounted. Power The power required to drive the agitator(s). OR: Power/Vol The power required to drive the agitator(s) expressed per unit volume. Enter the following values for the remaining General conditions: Vessel Diameter This is the fundamental quantity from which most of the others are derived. Once this value has been entered, the other quantities are entered as standard defaults by the program. These can be changed by the user as required. Bottom shape This is the shape of the vessel bottom. A correction factor is applied if the user specifies a flat bottom the default value is Dished. Page 42 of 86 PEW User Guide

43 Agitators Up to three impellers can be specified on a shaft. Once the first agitator is specified, the second and third are restricted to those types that can be correctly combined in this way. General options that can be specified for the agitators are: The number of impellers of the first type (1 to 3) If there are several identical impellers on the shaft then they only have to be defined once. Use this input to define how many identical impellers are present. Several non-identical impellers can be defined see below for details. Clearances The clearance is the distance from the agitator to the bottom of the vessel. There are two options Default and Supplied: Default The program does not ask for clearance information and positions the agitators at the recommended clearances. Note that the program moves them if the number of impellers are changed as this determines the clearances. Supplied The user is asked to enter clearances. The program checks that these are sensible values and displays warnings if they are not. The convention for ordering the impellers in this program is from the bottom of the vessel up. This is how they are arranged if Default clearances are selected. If the supplied clearances that indicate the impellers are in a different order, the calculation engine automatically renumbers them for the purposes of the calculation. Select the impeller type from the drop down box. Select one of the following: Rushton Flat Blade 45 Pitched 60 Pitched Propeller Anchor Gate Concave. Options for the second and third impeller are restricted by the choice for the first. The following details the required inputs for each impeller type: Rushton Number of blades The number of impeller blades. Impeller Diameter This is the most important data describing the impeller. If it is changed, the other dimensions of the impeller are reset automatically (these can be subsequently corrected if required). PEW User Guide Page 43 of 86

44 Clearance The clearance is the distance from the agitator to the bottom of the vessel. The program sets this automatically if default clearances were set at the previous prompt. Multiple impellers can be specified in any order but they will be arranged automatically at the end of editing so the first is the lowest. Blade width The dimension across the impeller blade. Blade thickness The dimensions through the thickness of the blade. Blade length The length of a single blade. Disc diameter The diameter of the disc on which the blades are supported. Disc thickness The thickness of the disc on which the blades are supported. Flat Blade Number of blades The number of impeller blades. Impeller Diameter This is the most important data describing the impeller. If it is changed, the other dimensions of the impeller are reset automatically (these can be subsequently corrected if required). Clearance The clearance is the distance from the agitator to the bottom of the vessel. The program sets this automatically if default clearances are set at the previous prompt. Multiple impellers can be specified in any order but they will be arranged automatically at the end of editing so the first is the lowest. Blade width The dimension across the impeller blade. Blade thickness The dimensions through the thickness of the blade. 45 and 60 Pitched Number of blades The number of impeller blades. Impeller Diameter This is the most important data describing the impeller. If it is changed, the other dimensions of the impeller are reset automatically (these can be subsequently corrected if required). Clearance The clearance is the distance from the agitator to the bottom of the vessel. The program sets this automatically if default clearances are set at the previous prompt. Page 44 of 86 PEW User Guide

45 Multiple impellers can be specified in any order but they will be arranged automatically at the end of editing so the first is the lowest. Blade width The dimension across the impeller blade. Blade thickness The dimensions through the thickness of the blade. Angle Blade angle to vertical. Blades pumping Whether the impeller pumps the liquid up or down. Propeller Number of blades The number of impeller blades the limit is three for this impeller type. Impeller Diameter This is the most important data describing the impeller. If it is changed, the other dimensions of the impeller are reset automatically (these can be subsequently corrected if required). Clearance The clearance is the distance from the agitator to the bottom of the vessel. The program sets this automatically if default clearances are set at the previous prompt. Multiple impellers can be specified in any order but they will be arranged automatically at the end of editing so the first is the lowest. Propeller pitch This can be compared to the pitch of a screw thread. It is the distance that would be travelled by the propeller it is was turned one revolution in a solid medium. Typical values range from D->2D where D is the diameter of the propeller. Anchor Impeller Diameter This is the most important data describing the impeller. If it is changed, the other dimensions of the impeller are reset automatically (these can be subsequently corrected if required). Clearance The clearance is the distance from the agitator to the bottom of the vessel. The program sets this automatically if default clearances are set at the previous prompt. Multiple impellers can be specified in any order but they will be arranged automatically at the end of editing so the first is the lowest. Edge clearance The clearance of the anchor from the walls of the vessel. Number of cross bars The number of horizontal bars that help to support the vertical bars of the gate. PEW User Guide Page 45 of 86

46 Gate Arm thickness The radial distance through the anchor blade. Impeller height The height of the anchor from its lowest point in the centre to the tops of its arms. Blade shape (round/flat) The shape of the anchor. This makes a difference in the clearance correction for the laminar and transitional regimes. Impeller Diameter This is the most important data describing the impeller. If it is changed, the other dimensions of the impeller are reset automatically (these can be subsequently corrected if required). Clearance The clearance is the distance from the agitator to the bottom of the vessel. The program sets this automatically if default clearances are set at the previous prompt. Multiple impellers can be specified in any order but they will be arranged automatically at the end of editing so the first is the lowest. Edge clearance The clearance of the anchor from the walls of the vessel. Number of cross bars The number of horizontal bars that help to support the vertical bars of the gate. Vertical bar spacing The external diameter of the vertical bars. Arm thickness The radial distance through the anchor blade. Impeller height The height of the impeller. Blade shape (round/flat) The shape of the anchor. This makes a difference in the clearance correction for the laminar and transitional regimes. Concave Blade Impeller Diameter This is the most important data describing the impeller. If it is changed, the other dimensions of the impeller are reset automatically (these can be subsequently corrected if required). Clearance The clearance is the distance from the agitator to the bottom of the vessel. The program sets this automatically if default clearances are set at the previous prompt. Multiple impellers can be specified in any order but they will be arranged automatically at the end of editing so the first is the lowest. Blade width The dimension across the impeller blade. Page 46 of 86 PEW User Guide

47 Blade thickness The dimension through the thickness of the blade. Blade radius The length of a single blade. Disc diameter The diameter of the disc on which the blades are supported. Disc thickness The thickness of the disc on which the blades are supported. Internals/Conditions The batch conditions are specified by entering the following data: Batch depth The depth of liquid in the vessel measured from the deepest point. Liquid density The average density of the liquid in the vessel. Liquid viscosity The normal (dynamic) viscosity of the liquid in the vessel. Note that these calculations are the Newtonian liquids only. The batch internals are chosen from a drop down box. The options available are: None 3, 4 or Normal Baffles 1 or 2 Beavertails 1 or 2 Two Finger Baffles 1 or 2 Dip Pipes Profiled Helical Coil Ringlet Coil Additional information is required for the Normal Baffles option and for the Helical Coil option. Note. Dip Pipes and Ringlet Coils have no effect unless the vessel is unbaffled. If they occur in baffled vessels, their additional effect can be ignored and the baffles themselves only have to be specified. Normal Baffles The following additional information is required: Baffle width The distance by which each baffle protrudes into the vessel. Baffle Height Baffles are normally either full or half height. The program handles non full height baffles by regarding any impeller above the baffles as unbaffled and any impeller with any part within the baffles as fully baffled. The type of baffle height specification the height of the baffle can either be described as a fixed proportion of the liquid height or as a specific height. PEW User Guide Page 47 of 86

48 Full The baffles are always taken to be the same height as the liquid in the tank. Half The baffles are always taken to be half the height of the liquid in the tank. Given The user is prompted for a baffle height. This height will not be reset by the program if you change the batch height this can be changed by the user as required. In the calculation, if an agitator has any part of itself within the baffled region it is treated as fully baffled. If it lies entirely outside the baffled region it is regarded as unbaffled. Baffle spacing The gap between the baffles and the wall. This is relevant if fouling is a problem. If space is present it is normally T/40 or T/60 where T is the tank diameter but the exact value is not critical. Select either of the following: None No gap between the baffles and the vessel walls. T/60 A gap 1/60 the size of the vessel diameter (T). Only a limited set of data is available for baffles for 45 and 60 Pitched blade impellers. The data set is restricted to: Four Baffles Wall-gap 4*T/12 flat wall baffles + T/40 wall-gap. No-gap 4*T/10 flat wall baffles + No gap. Half-Height 4*T/12 + wall-gap. Half height wall baffles. Helical Coils The following additional information is required: Tube diameter The diameter of the tubes from which the coil is composed. This is only required to check that the coils are not too closely spaced. Tube Pitch The gap between the coils. This is only required to check that the coils are not too closely spaced. Page 48 of 86 PEW User Guide

49 Equipment Inputs The following are the different types of calculation available for Equipment: Vessel Calibration Vessel Calibration This program calibrates depth, wetted area and volume for cylindrical tanks which may have flat, ellipsoidal, dished or conical ends independently of one another. Dished and conical ends may have a transition knuckle and the axis of the tank can be horizontal, vertical or inclined. See Appendix C for more information on Vessel Calibration. The following selections can be made: General data Mandatory. Select Orientation from one of the following: Horizontal Vertical Inclined. Enter the height of the upper end above the base in the Upper end height field. Select from either: Total Cylinder Length Enter values for: Total/Cylinder Length Dependent on which option was chosen above the total length of the vessel including ends or the cylinder length. Cylinder Diameter The diameter of the central cylinder. Density The density of the liquid or solid in the tank used to relate the volume of the contents to the mass. Note. All dimensions are vessel internal dimensions. Enter the following if the vessel axis is inclined: Upper and Height Height of the upper end above the base. End dimensions Enter values for: Shape Each end of the vessel can be either: Flat Straight across the end of the cylinder. Conical A cone with a rounded end which is linked to the main cylinder by a transition knuckle. PEW User Guide Page 49 of 86

50 Ellipsoidal An elliptical end with no transition knuckle. Dished Rounded end that is linked to the main cylinder by a transition knuckle. Enter the following depending on the type of shape chosen: Diameter of small end The diameter of the rounded end of the cone which is only required for conical ends. Cylinder end distance The distance from the end of the cylindrical portion of the vessel to the end of the cone which is only required for conical ends. Dished end radius or minor axis This is required for ellipsoidal and dished ends and has the following definitions: Ellipsoidal The minor radius of the ellipse. Dished The radius of the dished end. Radius of transition knuckle This is required for conical or dished ends which are assumed to be joined smoothly to the main cylinder by a curved transition knuckle. Calibration The vessel can be calibrated for the volume, mass or depth of contents. Select Calibrate from one of the following: Volume Mass Depth. Select Points from one of the following: Number Select the number of points to be calibrated, up to a maximum of 20 and the increment size is calculated by the program to cover the whole vessel. Increment Specify an increment size, and the program calculates increments starting at the base of the vessel until the whole vessel is calibrated, or 20 points are reached. If the increment size is too small to calculate the whole vessel, a warning message is given, an the final point gives the values when the vessel is full. Given The program can also calibrate to Given points. Set the number of points required (up to a maximum of 10) and supply each point in the given points fields. This allows uneven spacing of the calibration points. Page 50 of 86 PEW User Guide

51 2.3. Calculation Type Fittings Form The Fittings form allows Fittings losses to be specified for the compressible and incompressible flow calculation. The forms are only available for: Fluid flow Incompressible Fluid flow Compressible. The Fittings form is shown in Figure 3. Clicking the Edit pipe... button toggles between the Fittings section of the form at the bottom of the In/compressible flow window and the In/compressible flow section at the top of the Calculation Type window. Figure 3 Fittings section of the In/compressible flow window The following selections can be made from this dialog: Usage 90 degree bend The following define the type of bend: Circular A smooth bend that turns through a right angle. 2 cut mitre A bend with two elbows in it of 45 degrees each. 3 cut mitre A bend with three elbows in it of 30 degrees each. Note. For a 45 degree bend multiply the figure by 0.7 and for 180 degrees multiply by 1.4. These figures can be entered in the Miscellaneous losses cell. Radius/Diameter This is the ratio of the radius of curvature of the bend to the internal diameter of the pipe (The radius of curvature is taken to the centre line of the pipe). PEW User Guide Page 51 of 86

52 Usage Elbows Dead leg T junction Rectangular port plug valve Circular port plug valve The following define the type of elbow: 30 degrees A sharp turn through 30 degrees 45 degrees A sharp turn through 45 degrees 60 degrees A sharp turn through 60 degrees 90 degrees A sharp turn through 90 degrees A T-Junction with one leg blanked off with only one entry and one exit of the same diameter. Flow into leg The flow is into the blanked off part. Flow out of leg The flow is across the blanked off end (there is very little loss for flow past a blanked-off branch). The size of the port relative to the pipe area is shown in the prompt. The port size is the same as the pipe area for this data. Other valve types The values given for the following valves are all for turbulent flow through a fully open valve (see R A Smith). The adjustment factors for partly closed valves are given for each valve type. To account for a partly open valve, multiply the heads lost by the factor, and include the result in miscellaneous losses. Globe valve Gate valve There is no data for forged globe valves larger than two inches nominal diameter. % open Factor (approx.) Here the seat area is assumed to be the same as the pipe area. Note there is no data for valves smaller than 4 inches nominal diameter. % open Factor (approx.) Diaphragm valve % open Factor (approx.) Butterfly valve Miscellaneous losses Edit pipe The thickness of the valve is shown in the prompt. % open Factor (approx.) This can be used to enter any losses not specifically listed on the form. Clicking this button toggles between the Fittings section at the bottom of the window and the Inputs section at the top. Page 52 of 86 PEW User Guide

53 2.4. Calculation Types Results Forms The Results form displays the calculation results. The screen in Figure 4 shows the result when a Calculation type of Fluid flow/incompressible was calculated. Figure 4 Results section of the Calculation Type window Usage Warning/errors Any warnings messages that might have been generated while PEW was performing the calculation are displayed in this field in red text. PEW User Guide Page 53 of 86

54 2.5. Handling Calculation Results The following buttons on the toolbar (see section 2.7) allow the user to handle results in the following manner: Printing Results Creating a Graph Creating a Summary Table Printing Results On the Project menu clicking Print, or clicking the toolbar Print button, lets you select the following print options: Current calculation Current graph Summary Units Whole Project Prints the current calculation. Prints the current graph. Prints the Summary Table. Prints the Unit Settings form (see section for more information). Prints the whole project comprising the units settings, all the calculations and any summaries or graphs that have been created Creating a Graph Clicking this button generates a graph of the calculation. See section for an example Creating a Summary Table Clicking this button generates a Summary Table of the calculation. One a blank summary page has been created, cases and variables must be added to generate the summary. This is performed using the Summary/Add/Cases and Summary/Add/Variable menu items (see section for more information on the Summary menu and section for an example of how a Summary Table is created). Page 54 of 86 PEW User Guide

55 2.6. PEW Menus This section lists the various menus and describes the options that are available. Keyboard shortcuts are shown in brackets Project Menu The Project menu allows you to access the following options: Menu Option New Open (Ctrl-O) Include Save (Ctrl-S) Save As (Ctrl-A) Print (Ctrl-P) Print Setup Exit Definition Creates a new.pew project file. If there are any cases on the workbench, PEW prompts to save the current project first. The workbench will be re-initialised and all current cases, summaries and graphs removed. Cancel returns to the current project. Opens an existing.pew project file PEW prompts to save an existing project if appropriate. Once a project has been selected, the current project is closed and the selected project opened. Allows two or more projects to be combined. An existing project can be selected to add to the current project. All data in the current project, including the project name if set, remain, and the new data is added to it. Saves the project with the current filename (if one exists) and a.pew extension. Otherwise, PEW will prompt for a filename. All the cases in the current project are saved into one file with the specified filename and can be reloaded into PEW using the Project/Open command. Save the current project with a different filename. Allows the following print options: print the current calculation, summary or graph. print Units. print the whole project. To print a specific case, select it before choosing Project/Print. See section for more information. Displays the print setup dialog that allows settings (portrait, landscape etc.) to be changed. First prompts to save the current project then exits and closes PEW. PEW User Guide Page 55 of 86

56 Calculation Menu The Calculation menu allows you to access the following options: Menu Option Add Copy Calculate (F9) Delete Make default Definition Lists the calculation types available and creates a new case of the calculation chosen. The calculation types in PEW are divided into four groups: fluid flow, heat transfer, mixing and equipment. Multiple cases of the same calculation type can be opened. Creates a copy of the current calculation. Any data contained in the current calculation, including any calculated results are copied to the new calculation. This option can be used where a number of calculations on similar sets of data are required. Each calculation case only holds the data that is currently entered on it, and previous data will be lost, unless a copy of the calculation is used to carry out the next calculation. Runs the calculation for the currently selected case. The case data must be visible on screen, that is, the case must be shown in a window. This is because the data for minimised cases is stored temporarily to make more resources available to the system. Displays a warning and deletes the currently selected case unless Cancel is chosen. Makes the current case into the default for that calculation type. Subsequent new calculations of that calculation type have the initial data and units of the current case. These values are used in subsequent runs of PEW until a new case is made into the default or the built-in values are reset. This option can be used to specify a customised set of units for each calculation type. The data for the default cases is saved in a file called PEW.INI in the WINDOWS directory. To reset the default case to the built-in values either delete PEW.INI or edit it to remove the data for the relevant calculation type Edit Menu The Edit menu allows you to access the following options: Menu Option Copy Paste Copy Calculation To clipboard Definition Copies the selected text to the clipboard. Copies the text from the clipboard to the current field. Copies the calculation result to the clipboard. Page 56 of 86 PEW User Guide

57 Summary Menu The Summary menu allows you to access the following options: Menu Option Create Refresh Add Delete Graph Definition Creates an empty summary form to which the required cases and variables must be added. Updates the form with the latest information. First select: Case Then select: Variable One or more cases to add can be selected from the list of cases in the project. This can include cases which are currently visible or minimised. Cases of different calculation types can be added. If there is more than one summary in the project, the cases are added to the current summary. A summary can hold twenty cases. Once a case has been added to the summary, up to seven variables can be selected to display on the summary. A list of the variables available for all the cases on the summary is shown. If more than seven variables are selected, the first seven will be added and a warning given. Create another summary to show more than seven variables. Select one of the following: Case Variable One or more of the cases on the current summary can be deleted together with the variables associated with them. A variable type cannot be removed from the summary even if all the cases on which it appears are removed. If all cases on the summary are deleted, the summary is also be deleted. Any of the variables on a summary can be deleted. The cases remain so the summary is not deleted even if all the variables are deleted. A bar graph can be created to show any of the data on the current summary form. A list of cases on the summary is provided followed by a list of the variables on the summary, to choose from. These summary graphs can be titled, saved with the project and printed. However, the data on them cannot be changed after creation and the graphs are not updated if the cases or summaries change. For an updated version delete the old graph and create a new one. Note. To select multiple cases or variables at one time: Hold down the Ctrl key while clicking the selections to be chosen. PEW User Guide Page 57 of 86

58 Graph Menu The Graph menu allows you to access the following options: Menu Option Create X axis Y axis Second Y Delete second Y Definition Creates a graph to which variables can be added. The graph plots the values of the same variable on each case of a given calculation type. There must be at least two cases of the same type for a graph to be drawn. The program provides a list of the available calculation types. It then prompts for the X and Y axes from all the variables in the selected calculation type. If there are not enough calculations of any type to create a graph, the program displays a warning. Lists the variables available to select for the X axis. This can be used to change the x axis on the current graph. List the variables available to select for the Y axis. This allows the Y axis of the current graph to be changed. Adds a second Y variable to the graph. Deletes the second Y added by the option Second Y. Page 58 of 86 PEW User Guide

59 Units Menu The Unit menu allows you to access the following options: Menu Option Open Show Close Definition Opens the Units form (see Figure 5 below) to allow any unit to be changed or to use a different set of units. Changes to a unit take effect on all forms as soon as the focus is moved from the changed unit. This may take some time on a large project. Clicking Done on the form closes the form so giving a slight increase in available resources. If the Units form is open, clicking Show brings the form to the top and gives it focus. The effect is the same as clicking Units on the Window menu. Closes the Units form. Figure 5 Units Form There are three predefined sets of units: Engineering SI British. Click the appropriate button to select a set of units. The selected unit set appears in the cells at the bottom of the form. Changes to the current choice can also be made by typing the new unit into the appropriate cell. If the newly entered unit cannot be converted from the existing unit a warning appears and the change does not take place. PEW User Guide Page 59 of 86

60 Additional sets of units can be saved from the Save units set button. A prompts asks for a name and the units are saved in a file PEW.INI in the Windows directory. There is no limit to the number of unit sets but, if the same name is used twice, the new units set overwrites the old unit set with the same name. To reload a saved units set, click User and select the required set from the list. The default units set is initially Engineering. To change the default, first select the new units set then click Make default. The new units set is automatically loaded each time PEW is started. The Default option also selects this unit set Tools Menu The Tools menu allows you to access the following options: Pipe Inner Diameter Calculator Molecular Weight Calculator K-value Calculator Pipe Roughness Calculator Calculator Text Editor. Calculate Physical Properties Calculate Physical Property These are detailed in the following sections. Page 60 of 86 PEW User Guide

61 Pipe Inner Diameter Calculator This dialog is used to calculate the pipe inner diameter. Select a standard pipe size then the available schedules for that pipe size. The details for that combination are displayed at the bottom of the dialog box. Figure 6 Pipe Inner Diameter Calculator dialog The following selections can be made from this dialog: Usage Standard Pipe Sizes Lists the pipe sizes available from 1/8 to 36. Schedules Available Inner Diameter Wall Thickness Outside Diameter Return OK Lists the pipe schedules available for the pipe size selected. Displays the Inner Diameter of the selected pipe. Displays the Wall Thickness of the selected pipe. Displays the Outside Diameter of the selected pipe. Select which value is to be returned to the program. The default is Inner Diameter. Click OK to return the chosen value to the program. The value is pasted into the cell that was highlighted when the Pipe Inner Diameter Calculator was selected. PEW User Guide Page 61 of 86

62 Molecular Weight Calculator This calculates the molecular weight of a compound given its formula. The following rules are used to interpret the formula: Elements are given their usual atomic symbol, for example, He for Helium and O for Oxygen. The first character must always be upper case and the second (if there is one) lower case. This enables the Molecular Weight Calculator to distinguish formulae such as PO and Po. The calculator regards the first of these as Phosphorous and Oxygen and the second as the element Polonium. No other symbols are recognised, for example, common groups like benzene rings, ethyl groups etc. Elements can be followed by numbers and are separated by spaces, dots or colons. Brackets can be used as required to any level. For example, CH3(CH2)10CH3 would be one way of describing Dodecane (see Figure 7). However, note that in this example the 10 refers to the CH2 group, not the succeeding CH3. Thus water of crystallisation must be specified as Na3SO3(H2O)5. The atomic weights used by the Molecular Weight Calculator are taken from Perry s Chemical Engineers Handbook. Figure 7 Molecular Weight Calculator dialog The following selections can be made from this dialog: Usage Enter Chemical Formula Mol. Weight OK Enter the chemical formula then click the = button to calculate the molecular weight. Outputs the molecular weight for the formula entered. The molecular weight calculated is automatically pasted into the cell that currently has focus when the dialog is closed. If this cell does not accept the value it is pasted to the clipboard instead. Click OK to paste the calculated value into the cell that was selected when the Molecular Weight Calculator was run. Page 62 of 86 PEW User Guide

63 K-value Calculator The Fittings Loss (K-value) calculator consists of a number of sections where the fitting's details of a pipe are built up. The front sheet of the dialog contains a summary of the following sections: Tee Junctions Bends Valves Expansions/Contractions User Defined (Process Equipment) Manual Adjustment. Figure 8 Fittings Loss (K-value) Calculator dialog The following selections can be made from this dialog: Usage Summary Tab: - Sub Total Outputs the sub total before a manual adjustment is added. - Manual Adjustment The manual adjustment field is for entering miscellaneous fittings. It is also used for manually adjusting the model in the validation stage or for studying the effect of changes, for example, changing a control valve position. - Reason for Adjustment Text describing the reason for adjustment can be entered in this field. - Overall Total Outputs the overall total combining the sub total and the manual adjustment to produce the fittings loss value for the fitting. PEW User Guide Page 63 of 86

64 Tee Junctions Tab: The Tee Junctions calculation takes into account any blanked off junctions. This can also be a line where the dead leg is isolated at a valve further downstream. Add a Tee Junction: Remove a Tee Junction: Select a Tee Junction Type, enter the Quantity and click Add. The entry is added to the list at the bottom of the sheet. Select the Tee Junction then click Delete. An example of a typical Tee Junction tab display is shown below: Bends Tab: Bends are entered and deleted using the same method as for Tee Junctions. An example of a typical Bends tab display is shown below: Page 64 of 86 PEW User Guide

65 Valves Tab: Valves are entered by selecting a valve type then double-clicking it. This displays the various categories of valve available for that type, for example, the Globe Valve type has two categories cast valves and forged valves (see below). Add a Valve: Click the category required and select a valve from the Pipe Size (Nominal Bore) drop down list. Specify how many of these valves are required in the Quantity box then click Add. Delete a valve: Select the valve from the list and click Delete. An example of a typical Valves tab display is shown below: Contractions/Expansions Tab: Click either Expansion or Contraction then follow the same method as for Tee Junctions. For exit losses: For entry losses: Select an expansion with a small/large area ratio of zero. Select a contraction with a small/large area ratio of zero. An example of a typical Contractions/Expansions tab display is shown below: User Defined (Process Equipment) Tab: The easiest way to model process equipment (for example, heat exchangers and filters) is as a section of pipe with a fitting loss coefficient. The pipe length needs to be short so that the pressure drop is solely due to the fittings 1m is generally used. The values for mass flow, pressure drop etc. can be obtained from the process datasheet. PEW User Guide Page 65 of 86

66 Static head changes between inlet and outlet should not be taken into account as the node information deals with this. An example of a typical User Defined (Process Equipment) tab display is shown below: Note. The K-value is automatically posted into the cell that is currently active when the K-value dialog is closed. This value is pasted to the clipboard if the cell does not accept the value Pipe Roughness Calculator This calculator is used to select a Surface Type and Absolute Roughness. Clicking OK then adds the selection to the calculation. The units of measurement for roughness depend on the program calling the Pipe Roughness Calculator. Those for PIPER are in mm. For other programs (for example, FLONET) the Pipe Roughness Calculator displays and returns the relative roughness based on the relevant pipe diameter. By default, the units are in mm for PEW and the Absolute Roughness is returned. Figure 9 Pipe Roughness Calculator dialog Calculator Opens the Windows Calculator to assist with your calculations Text Editor Opens the Notepad text editor. Page 66 of 86 PEW User Guide

67 Calculate Physical Properties The PPDS Calculator is used to calculate physical properties for a fluid, such as its density and viscosity. The properties to be calculated depend on which type of calculation case the calculator is run from. The example dialog shown in Figure 10 is run from an Incompressible Flow form. On some forms the properties are grouped into more than one stream. For example, for the Two Phase flow form liquid and gas properties are grouped separately. Similarly, the pipe and vessel heat loss forms group have properties at several different temperatures. The dialog consists of two separate sections. The component section at the top of the dialog lets you define the constituent parts of the fluid. Whenever you open the calculator the table always contains the last values used. This lets you run multiple calculations on the same fluid without having to specify the fluid each time. The lower section of the dialog is the properties calculator itself. Figure 10 PPDS Calculator dialog The following selections can be made from this dialog: Usage Component section: Add Component Opens a search dialog to let you add a component to the table. Select a Databank to search and type a search string. Select the required component in the results list and click Add to stream. Add as many components as you need then click Close. PEW User Guide Page 67 of 86

68 Clear Worksheet Select Units Mol Wt Molar (kmol) Mol. Fraction Mass (g) Mass Fraction Clears the values you used last time, so that you can specify a new fluid. Opens a separate dialog that lets you specify the units for Temperature Pressure Molar Amount Mass Amount To change a unit, right-click the cell and select an alternative in the shortcut list. Then click OK. The molecular weight is automatically entered for the component and cannot be changed. Enter the molar amount of each component. Enter the molar fractions or relative amounts of each component. (these are then normalised and displayed as fractions). Enter the mass amount of each component. Enter the mass fractions or relative amounts of each component.(these are then normalised and displayed as fractions). Calculator section: Phase Temperature, Pressure Calculate Select one of the following from the list: Liquid, Vapour, Ideal Gas Enter the temperature and pressure to be used in the calculation. You can enter these in different units (see Appendix A) Click Calculate to compute values for the properties OK Click OK to paste the calculated values into the group of cells, one of which was selected when the PPDS Calculator was run Calculate Physical Property This second option also calls the PPDS calculator, but only to calculate a single fluid property Window Menu This menu consists of the standard Windows options, that is, Cascade, Tile (horizontal and vertical), Arrange Icons and a list of all available windows Help Menu The Help menu provides on-line help information, a search facility and the latest version information. Page 68 of 86 PEW User Guide

69 2.7. The PEW Toolbar The toolbar buttons run the following commands: Button Purpose New Project Creates a new PEW project. Equivalent Project menu item New Open a saved Project Opens an existing (saved) PEW project Equivalent Project menu item Open Save Project Saves the PEW project currently open. Equivalent Project menu item Save Print the current Project Print the current PEW project. Equivalent Project menu item Print Add a new Case Displays the Calculation type dialog. Equivalent Calculation menu item Add Copy the current Case Creates a copy of the current calculation. Equivalent Calculation menu item Copy Calculate the current Case Runs the calculation for the currently selected case. Equivalent Calculation menu item Calculate Delete the current Case Displays a warning and deletes the currently selected case unless Cancel is chosen. Equivalent Calculation menu item Delete Create a Summary Creates an empty summary form to which the required cases and variables can be added. Equivalent Summary menu item Create a Summary Create a Graph Creates a graph to which variables can be added. Equivalent Graph menu item Create a Graph Set X axis for Graph Lists the variables available to select for the X axis. Equivalent Graph menu item Set X Axis PEW User Guide Page 69 of 86

70 Button Purpose Set Y axis for Graph Text... Lists the variables available to select for the Y axis. Equivalent Graph menu item Set Y Axis Add a variable to the current summary One or more cases can be selected and added from the list of cases in the project. Equivalent Summary menu item Add a case to the current summary Add a case to the current summary One or more variables can be selected and added from the list of variables in the project. Equivalent Summary menu item Add a variable to the current summary Set numeric format for the calculations The selection can be made from one of the following formats: This sets the number of significant figures, not the number of decimal places. This means that choosing the fourth option indicates that only four significant figures will be displayed. The value would be displayed as under these circumstances. Display PEW helpfile Displays the PEW on-line help. Pressing F1 while a particular cell is selected displays the help file for that input value. Page 70 of 86 PEW User Guide

71 3. PEW Tutorial 3.1. General This example details the procedure to calculate the flowrate of water in 500 feet of 2 inch unlined cast iron pipe up a 10 foot incline for pressure drops between 0.5 and 3 bar diff. There is one 90 circular bend in the pipe and five velocity heads lost in other fittings Solving the Network The procedure to solve the network involves the following steps: Accessing PEW Selecting the Calculation type Entering data on the Inputs form Entering data on the Fittings form Performing the Calculation Repeating the calculation for other values. The results can then be viewed, graphed, printed and saved Starting PEW Procedure 1. Click Start > All Programs > PEL then click the PEW icon. Note. If using the classic Start menu or earlier versions of Windows, click Start > Programs A splash screen showing the program name and version number appears briefly before the start up screen (see Figure 1) appears Selecting the Calculation type Procedure 1. On the Calculation menu, click Add or click the Add a new case button on the toolbar. 2. In the Calculation type window, click Fluid flow in the left pane and Incompressible in the right pane. Figure 11 Selecting the Calculation type 3. Click OK. The Incompressible Flow form opens. PEW User Guide Page 71 of 86

72 Entering pipework and losses data on the Inputs form Procedure 1. Click Flow (just underneath the heading Calculate) to select the Flow calculation. 2. Double-click the Pipework Length box to select the default value of 10m. 3. Enter the value 500 followed by a space followed by ft. Press Enter on the keyboard or click another input box to perform the conversion automatically (see Appendix A for more information about in-cell units conversion). 4. Double-click the Pipework Diameter box to select the default value. On the Tools menu, click Pipe Inner Diameter Calculator. 5. Leave the type set to Steel Pipe, Select a 2 and 40 /STD/ 40S pipe then click OK. PEW pastes the internal diameter into the Pipe Diameter box. The Lining thickness box is not used in this calculation as the pipe is unlined. 6. Double-click the Pipework Roughness box to select the default value. On the Tools menu, click Pipe Roughness Calculator. Select Cast iron, concrete, timber and then click OK. PEW pastes the result into the Roughness box. 7. Double-click the Losses Static head loss box to highlight the default value. Enter the value 10 ft. 8. The Pipework and Losses sections now looks like this: Entering data on the Fittings form Procedure 1. Click Edit to the right of the legend Fittings loss (velocity heads) to switch to the Fittings section. 2. Go to first cell in the Number of Items column and enter the value 1 to specify a single 90 circular bend. 3. Go to the Miscellaneous losses box at the bottom of the form and enter the value 5 to specify five velocity heads lost through other fittings. 4. Click Edit pipe to switch back to the main input form. Page 72 of 86 PEW User Guide

73 Calculating fluid properties and process conditions data Procedure 1. Click in the Density box. On the Tools menu, click Calculate Physical Properties. 2. When the Calculator appears, if any components appear in the worksheet click Clear Worksheet to clear them. 3. Click Add Component to open the Select Components dialog. Enter water in the Search for Name box, select WATER in the results list and then click Add to stream to add water to the Calculator and then click Close. 4. Enter a temperature of 20 C and a pressure of 1 bar and click Calculate. The Calculator returns a density of kg/m3 and a viscosity of Click OK to return these values to the Incompressible Flow form. 5. Double-click the Pressure drop to select the default value and enter 0.5 bar diff. 6. The Inputs and Fittings forms of the Incompressible flow window now look like this: Figure 12 Inputs section of the Incompressible data Input window PEW User Guide Page 73 of 86

74 Figure 13 Fittings section of the Incompressible data Input window Performing the Calculation Procedure Click the Calculate button on the toolbar. The results appear (in blue text) in the Results form on the right of the Calculation type window as shown in Figure 14 when the calculation has finished. Note. Any warnings or errors produced during the calculation are displayed at the bottom of the results form in red text. Figure 14 Results section of the Incompressible data Input window The value kg/s for the Mass flow appears. Page 74 of 86 PEW User Guide

75 Repeating the calculation for other values It is necessary to repeat the calculation over a range of pressure drops between 0.5 and 3 bar. This is performed at 1, 2 and 3 bar. However, each set of results must be saved so the calculation should be copied before making the changes. Procedure 1. Click the Copy button on the toolbar. This produces a copy of the first case. Change the title from Copy of No 1 to No Double-click the Pressure drop field and change the value to 1 bar diff. 3. Click the Calculate button on the toolbar to re-calculate the flowrate. This should produce a value of kg/s for the flowrate. 4. Repeat the last three steps for pressure drops of 2 and 3 bar diff. This should produce flowrates of and kg/s respectively Plotting the Graph Procedure 1. Click the Create a graph button on the toolbar. 2. In the Graph select calculation type dialog, click Incompressible and then click OK. 3. In the Graph select X axis dialog, click Pressure drop and then click OK. 4. In the Graph select Y axis dialog, click Mass flow and then click OK. 5. The following graph appears: Figure 15 Graph of Pressure drop against Mass flow 7. On the Project menu click Print, or click the toolbar Print button, to produce a paper copy of the graph. PEW User Guide Page 75 of 86

76 Creating a Summary Table Procedure 1. Click the Create a summary button on the toolbar and enter Demonstration as the summary title. 2. Click the Add a case to the current summary button on the toolbar. 3. In the Summary select case dialog, select all four cases, and then click OK. 4. Click the Add a variable to the current summary button on the toolbar. 5. In the Summary select variable dialog, select Pressure drop, Massflow, Velocity and Reynolds number as the columns for the table and then click OK. The following Summary Table appears. Figure 16 Summary Table 8. On the Project menu click Print, or click the toolbar Print button, to produce a paper copy of the Summary Table. Page 76 of 86 PEW User Guide