Joint Expo 2012 February 7-8, 2012 BASIC HYDRAULICS

Transcription

1 Tim Sullivan, P.E. Hubbell, Roth & Clark, Inc.

2 Outline Pressure Hydraulic Energy and Head Losses System-Pump Curves Concepts of hydraulics as they relate to Operators and Mechanics

3 Outline Good News Bad News

4 Outline Formulas & Math

5 Outline Good News? No Test

6 Outline Formulas & Math

7 Pressure Depth Weight Pressure = of x of Water Water

8 Pressure (ft) 1 ft PSI 4 1 ft 2 ft PSI 2 ft 3 ft PSI 4 3 ft

9 Pressure (in psi)

10 Pressure (psi per ft) 2.3 ft PSI 4 1 psi 4.6 ft PSI 2 psi 6.9 ft PSI 4 3 psi

11 Pressure (psi per ft) 50 psi 2.3 ft PSI 4 51 psi 4.6 ft PSI 52 psi 6.9 ft PSI 4 53 psi

12 Pressure (Gauge vs Absolute) psi g & psi a psi a = psi g psi

13 Pressure (Gauge vs Absolute) 14.7 psi Absolute Gauge psi a 2.3 ft PSI 4 1 psi g 16.7 psi a 4.6 ft PSI 2 psi g 17.7 psi a 6.9 ft PSI 4 3 psi g

14 Pressure Is all pressure positive?

15 Pressure (Suction Lift)? psi PSI ft Water Lever

16 Pressure (Suction Lift) -10 psi PSI ft Water Lever

17 Compound Gauge PSI 20

18 Pressure (Suction Lift) Water Level 10 psi -10 psi PSI PSI ft Total Pressure developed by pump 23 ft = 20 psi Water Level

19 Pressure (Water(?) Cooler) 1ft negative pressure 1ft

20 Hydraulic Energy Bernoulli Theorem

21 Hydraulic Energy

22 Hydraulic Energy Bernoulli Theorem Pressure (ft) Velocity (ft) Height (ft)

23 Pipe Pressure 50 psi PSI ft 60 psi PSI 100

24 Pipe Pressure - Energy psi + 23 ft PSI PSI 50 psi + 23 ft 60 psi + 0 ft 23 ft PSI 100 Constant Diameter

25 Pipe Velocity Energy Kinetic Energy = Velocity Head

26 Pipe Velocity Energy EGL PSI 100 Pressure Energy Decreases Kinetic Energy Increase 50? PSI Kinetic Energy Pressure Energy PSI 100 HGL 50 psi 50 psi Flow 1 V 1 V V 3

27 Pipe Pressure Eductor EGL Kinetic Energy Pressure Energy HGL 50 psi 50 psi PSI ? PSI 0 PSI 100 Very Fast Flow 1 V 1 V V 3 Negative Pressure = Vacuum

28 Bernoulli Theorem in air Fast Air Velocity LOWER Air Pressure Air travels over top and bottom The air over the top travels farther thus faster The lower air pressure on the top creates lift

29 Pipe Pressure - Energy Real World: Energy A = Energy B + Losses

30 Pipe Pressure - Energy PSI psi 50 psi PSI psi 23 ft PSI 100 No Flow

31 Pipe Pressure - Energy PSI psi psi PSI psi 23 ft PSI 100 Some Flow

32 Pipe Pressure - Energy PSI psi psi PSI psi 55 psi 23 ft PSI 100 Lotsa Flow

33 Pipe Pressure - Energy Engineers spend a lot of time with HEADLOSS

34 Headloss Minor Losses Friction Losses

35 Minor Loss Water moving through: Valves Fittings Entrance/Exit Reducers

36 Major Loss?

37 Minor Loss Values of K: 0.2 = Gate Valve 0.5 = 90 Bend 1.5 = Tee 2.0 = Swing Check Valve 10.0 = Disk Check Valve 70.0 = Ball Check Valve!

38 Minor Loss if K = 23, V = 8 fps, then: = 23 ft pressure loss = 10 psi pressure loss

39 Friction Loss

40 Friction Loss Length & Headloss

41 Friction Loss Diameter & Headloss

42 Friction Loss

43 Friction Loss Diameter & Headloss?

44 Friction Loss Diameter & Headloss

45 Be Careful of True Diameter 12 Ductile Iron 12 HDPE O.D. = 13.1 I.D. = 12.2 O.D. = 13.2 I.D. = 10.8

46 Be careful of the diameter of your glass Although they restricted themselves to one drink at lunch time, Howard and Tom still found they were not at their most productive in the afternoons

47 Friction Loss + Minor Loss K

48 Friction Loss + Minor Loss Is this going somewhere? Yep..System Curve then Pump Curve

49 System Curve 2 System Extremes 1. Lift Station 2. Force Main

50 System Curve Lift Station High Static Lift Low Losses

51 System Curve Lift Station E Static Lift

52 System Curve Lift Station E Static Max Min Static Lift Lift Wet Well Level High Low

53 System Curve TDH (ft) Losses Min Static Lift Max Static Lift Flow (gpm)

54 System Curve Force Main Little/no static lift High losses

55 System Curve Lift Station E

56 System Curve TDH Same Duty Point Flow (gpm)

57 Pump Curve TDH Flow (gpm)

58 Pump Curve Allowable Operating Range TDH Preferred Operating Range Flow (gpm)

59 Pump Efficiency BEP 80% 70% TDH 60% Flow (gpm)

60 Pump Curve BEP TDH Flow (gpm)

61 Pump Curve Add Valves And Pipe TDH Flow (gpm)

62 Pump Curve TDH Increase Diameter Flow (gpm)

63 Variable Frequency Drive (VFD) TDH 40 Hz 45 Hz 50 Hz 65 Hz 55 Hz Flow (gpm)

64 Variable Frequency Drive (VFD) BEP TDH 40 Hz 45 Hz 50 Hz 65 Hz 55 Hz Flow (gpm)

65 Variable Frequency Drive (VFD) BEP TDH 40 Hz 45 Hz 50 Hz 65 Hz 55 Hz Flow (gpm)

66 Title? PSI PSI 100

67 Title? PSI PSI PSI PSI 100

68 Joint Expo 2013 Open Channel Flow? Questions? Thank You Tim Sullivan IS GOING TO MESS SOMEBODY UP