CFD Analysis and Experimental Study on Impeller of Centrifugal Pump Alpeshkumar R Patel 1 Neeraj Dubey 2

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1 IJSRD - International Journal for Scientific Research & Development Vol. 3, Issue 2, 21 ISSN (online): Alpeshkumar R Patel 1 Neeraj Dubey 2 1 PG Student 2 Associate Professor 1,2 Department of Mechanical Engineering 1,2 Sagar Institute of Research & Technology, Bhopal Abstract The experiment testing of centrifugal pump can give the actual value of head, efficiency and power rating. But the internal flow conditions cannot be predicted by experimental results. Computational Fluid Dynamics analysis is advanced tool for prediction of flow analysis in pump industry, which predict the internal flow pattern inside the impeller, in this paper experimental testing were conducted on centrifugal pump. The existing impeller of centrifugal pump was used and design data was measured with geometrical method. Model of existing impeller was created in SOLID EDGE ST The CFD analysis of Centrifugal pump impeller has been carried out using ANSIS-CFX. Different characteristic curves like, head vs flow rate, power and efficiency is plotted with CFD Analysis result and validate with experimental test result. Key words: Centrifugal Pump Impeller, SOLID EDGE ST4, CFD Analysis I. INTRODUCTION Centrifugal pump is most common pump used in industries, agriculture and domestic application. A centrifugal pump is a rotodynamic pump that uses a rotating impeller to increase the pressure and flow rate of a fluid. Centrifugal pumps are the most common type of pump used to move liquids through a piping system. The fluid enters the pump impeller along or near to the rotating axis and is accelerated by the impeller, flowing radially outward or axially into a diffuser or volute chamber, from where it exits into the downstream piping system. Centrifugal pumps are typically used for large discharge through smaller heads. Fig. 1: Centrifugal Pump The construction of this type of pump consists of a single rotating element and a simple casing, which can be constructed using a wide assortment of materials. Casing centrifugal pump casing either of volute or diffuser type. Impeller centrifugal pump impellers are classified open, semi open and enclosed impeller. II. USE OF COMPUTATIONAL FLUID DYNAMICS (CFD) Computational fluid dynamics (CFD) is one of the branches of fluid mechanics that uses numerical methods and algorithms to solve and analyze problems that involve fluid flows. In order to shorten the design periods and lowering the manufacturing, prototyping and test costs of the pump, commercial Computational Fluid Dynamics (CFD) software is used in the design procedure. The main aim of this study by means of applying numerical experimentation to the designed pump is CFD code integration into the design procedure and verification of the design before the pump is produced. The CFD code is used to obtain pump characteristics curves such as head vs. flow rate and efficiency vs. flow rate. Working in CFD is done by writing down the CFD codes. CFD codes are structured around the numerical algorithms that can be tackle fluid problems. In order to provide easy access to their solving power all commercial CFD packages include sophisticated user interfaces input problem parameters and to examine the results. Hence all codes contain three main elements: 1) Pre-processing. 2) Solver 3) Post - processing. III. EXPERIMENTAL TESTING RESULTS In this experiment M12 centrifugal pump is used. The schematic diagram of experiment is shown in fig. the flow rate is adjusted through the discharge valve, which is located after the pump. Bourdon gauges are mounted at the suction and discharge sides of the pump. The flow rate is measured using Rotameter. A Rotameter is a device installed vertically, which is operates when upward fluid drag on the float is balanced by the weight of the float. Power analyzer is used for measuring volt, ampere which is used for obtaining the power input to the motor of the centrifugal pump. Discharge (m 3 /hr) Total Head (m) Pump Efficiency (%) Rated Pump Input (Kw) RPM Table 1: Experimental Results No. of Blade 6 Blades Inlet Diameter 86 mm Outlet Diameter 144 mm Shaft Diameter 24 mm Eye Diameter 6.2 mm Blade Thickness at Inlet 3 mm Blade Thickness at Outlet 3 mm Inlet Blade Angle 4.3 degree outlet blade angle 26.4 degree All rights reserved by

2 (IJSRD/Vol. 3/Issue 2/21/36) Table 2: Design Data of Existing Impeller IV. MODELING OF EXISTING IMPELLER After geometrical measurement of M-12 impeller, the modeling has been performed on the SOLID EDGE ST Fig. 4: Meshing of Impeller Fig. 2: Existing Impeller Fig. 3: Modelling of Impeller V. MESHING OF IMPELLER Modelled developed in first stage is than exported to ANSYS Turbo Grid. ANSYS Turbo Grid is very powerful tool, which create high quality hexahedral meshes, while preserving the underlying geometry. These meshes are used in the ANSYS work flow to solve complex blade passage problem. Mesh type Coarse Number of nodes 74 Number elements Element type Hexahedra Brick Element Table 3: Mesh Statistics A. Boundary Conditions: VI. CFD ANALYSES The developed mesh model is than exported to the CFX-Pre which is the per processing stage. At this stage the problem is evaluated by providing initial conditions like boundary conditions, domain physics, running conditions etc. Initial conditions are described below provides input to the processor. Domain physics for impeller Location Medium Material Models Passage Fluid Water Turbulence model= k- epsilon Turbulent Wall Functions= Scalable Domain Motion=Rotating Table: Flow Direction Normal to Boundary Reference Pressure 1 [atm] Turbulence Shear Stress Transport Wall Influence On Flow No Slip Wall Roughness Smooth Wall Table: 6 Fig. : Boundary Condition Fig. 6: Inlet Boundary Condition All rights reserved by

3 (IJSRD/Vol. 3/Issue 2/21/36) Fig. 7: Outlet Boundary Condition B. Pressure and Velocity Distribution in Impeller Blades: The total pressure distribution between the blades of the impeller is shown in fig.8. The lowest pressure is the pressure, which appear at the inlet of the impeller suction side. The highest total pressure occurs at the outlet of impeller, where the kinetic energy of flow reaches maximum. Fig. 1: Velocity Vectors at % Span Fig.11 shows contours of circumferentially area averaged velocity (Cm) and Fig.12 shows pressure (P) streamlines at the trailing edge which shows that how the flow leaves the blades of the impeller. Fig. 8: Contours of Ptr at % Span The static pressure distribution at the span of % between the blades of the impeller is shown in fig. 9. Fig. 11: Contours of circumferentially Area-averaged velocity Fig. 9: Contours of P at % Span The relative velocity distribution at % span between two blades of the impeller is shown in fig. 1. Fig. 12: Contours of circumferentially Area-averaged pressure C. Blade Loading At Pressure and Suction Side: The blade loading of pressure and suction side are drawn on the blade at the span of % from hub towards the shroud. The pressure loading on the impeller blade is shown in fig 13. Pressure load on the impeller blade is plot along the stream wise direction. The pressure difference on the pressure and suction sides of the blade suggests that the flow inside the impeller experiences the shearing effects due to the pressure difference on blade-to-blade passage wall. All rights reserved by

4 EFFICIENCY HEAD POWER EFFICIENCY (IJSRD/Vol. 3/Issue 2/21/36) Fig. 16: CFD Result Curve Efficiency Vs Discharge 7. Fig. 13: Blade Loading At % Span Fig. 17: CFD Result Curve Power Vs Discharge Fig. 14: Shows the Stream Wise Area Averaged Velocity (Cm) Versus Averaged Normalized M Results obtained after the CFD Analysis are Following graphs. VII. COMPARISON CHARTS OF TEST AND ANALYSIS RESULT Results obtained by Experimental work and the CFD Analysis are plotted on the same graph for the Comparison VS HEAD 1 EXPERIMENTAL HEAD CFD HEAD Fig. 1: CFD Result Curve Total Head Vs Discharge Fig. 18: Flow Rate Vs Head VS EFFICIENCY EXPERIMENTAL EFFICIENCY CFD EFFICIENCY Fig. 19: Flow Rate Vs Efficiency All rights reserved by 14

5 POWER (IJSRD/Vol. 3/Issue 2/21/36) VS POWER EXPERIMENTAL POWER CFD POWER Noise,IJERA, ISSN: , Vol. 2, Issue4, July-August (212). Fig. 2: Flow Rate Vs Power VIII. CONCLUSIONS The design and analysis of centrifugal pump impeller is done and different characteristic curves, Flow Rate Vs. Discharge, Efficiency Vs. Discharge, Power Vs. Discharge are plotted. The experiments are carried out at various operating condition and results obtain by experiments are compared with CFD Analysis results. At 17.2 m head efficiency obtained by CFD analysis is 7.6 % which is satisfactory. The efficiency of the centrifugal pump can be improved by increasing the value of surface finish factor. The impeller is the important component of the centrifugal pump which plays a crucial role in determining the efficiency of the centrifugal pump. REFERENCES [1] A. Manivannan, Computational fluid dynamics analysis of a mixed flow pump impeller, International Journal of Engineering, Science and Technology, 21. [2] P. Usha Sri, C.Syamsundar. Computational Analysis on performance of a centrifugal pump impeller (21). [3] Erik dick, Jan Vierendeels, Sven Serbruyns And John Vande Voorde. Performance Prediction of centrifugal pumps with CFD-Tools (21). [4] Peter Hlbocan, Michal Varchola Prime Geometry Solution of a Centrifugal Impeller within a 3D setting,(212). [] Michal Varchola,Peter Hlbocan, Geometry Design of a Mixed Flow Pump Using Experimental Result of on Internal Impeller Flow (212). [6] Shardul Sunil Kulkarni Parametric Study of Centrifugal Pump and its Performance Analysis using CFD,ISSN , ISO 91:28 Certified Journal, Volume 4, Issue 7,( July 214). [7] S.Rajendran, Dr.K.Purushothaman Analysis of a centrifugal pump impeller using ANSYS-CFX IJERT, ISSN: , Vol. 1 Issue 3, (May 212). [8] A Syam Prasad, BVVV Lakshmipathi Rao, A Babji, Dr P Kumar Babu Static and Dynamic Analysis of a Centrifugal Pump Impeller IJSER, ISSN , Volume 4, Issue 1, (October- 213). [9] Amit Suhane Experimental Study on Centrifugal Pump to Determine the Effect of Radial Clearance on Pressure Pulsations, Vibrations and All rights reserved by 141