ISSN 2395-1621 CFD Analysis for Designing Fluid Passages of High Pressure Reciprocating Pump #1 SuhasThorat, #2 AnandBapat, #3 A. B. Kanase-Patil 1 suhas31190@gmail.com 2 dkolben11@gmail.com 3 abkanasepatil.scoe@sinhgadedu.in #13 Department of Mechanical Engineering,S.C.o.E., SPPU Pune, India #2 Dampf-Kolben, Pune, India ABSTRACT Reciprocating pump is a positive displacement device. They are used to pump fluids and serve in special applications that demand low flow rates against high resistance. High pressure (50 bar) reciprocating pumps are designed as per industrial applications. Normally they are designed with past experience and modifications are carried out by trial and error method. Keeping this view in mind the design parameters need to be analyzed for optimum design condition. Computational fluid dynamics (CFD) is being increasingly applied in the design of the reciprocating pumps. In this study different diameter of discharge chambers is investigated. The varying parameters like different discharge chamber diameter and speed is studied. It is very difficult to check pump performance by varying discharge chamber diameters practically. CFD tool is used for simulation of flow, which is less expensive and easy to modify. Present work is aimed to study pump performance at different positions of plunger using ANSYS/Fluent CFD software. ARTICLE INFO Article History Received :18 th November 2015 Received in revised form : 19 th November 2015 Accepted : 21 st November, 2015 Published online : 22 nd November 2015 Keywords Plunger CFD, Designing of fluid passages, High pressure reciprocating pump, I. INTRODUCTION Pump is used to transport fluid from one reference point to the other. Pumps are classified in different ways such as centrifugal pump, gear pump, reciprocating pump. Pump is selected on the basis of operating pressure, overall efficiency, discharge and cost. In reciprocating pump, the fluids enter the pump cylinder through the inlet valve and get compressed by the piston force to the desired pressure. The outlet valve delivers the compressed fluid to the required height. Tsui and Lu [1] evaluated the performance of a valvelessmicropump by CFD. The result shows that at 2000 Pa back pressure simulation, pump mode and supply mode efficiency was 4%, 9% and 15% respectively. Kumar and Bergada [2] studied the effect of piston grooves on performance in an axial piston pumps using CFD analysis. They found that grooves placed towards the inner edge of the piston produces 1.5% higher force on piston surface with respect to the non-grooved piston. Fan et al. [3] studied computational fluid dynamic analysis and design optimization of jet pumps. The result shows pump efficiency increases from 29 % to 33 %. The energy requirement of the pump was reduced by 20%. Alves et al. [4] studied analytical and CFD modelling of the fluid flow in an eccentric tube centrifugal oil pump for hermetic compressors. They observed maximum flow rates for an inclination angle of 68. Kumar et al. [5] studied analysis of axial piston pump grooved slipper by CFD simulation. Static and dynamic characteristics of a piston pump slipper with groove were investigated. The result indicates that the slipper leakage at 10 MPa inlet pressure for 17 microns true 2015, IERJ All Rights Reserved Page 1
clearance was 0.10 l/min and 17 microns CFD clearance was 0.082 l/min. Pei et al. [6] carried numerical and experimental work to study the collision characteristics for reciprocating pump.the valve disc motion parameters have been measured directly by displacement and acceleration sensor, where both are mounted on the valve disc. Approximation theory has 2.12% less displacement of valve disc as compare to U.Adolph theory for stroke of 200(times/min). Kumar et al. [7] studied optimization of connecting rod parameter using CAE tools. The result indicated that the weight of the connecting rod was reduced by 0.004 Kg. The percentage reduction of weight was 3.05 %.Parkash et al. [8] studied optimization of design of connecting rod under static and fatigue loading. The comparisons for static and fatigue loading have been studied under same boundary condition. The result indicated that the weight of connecting rod was reduced by 0.005 Kg. The percentage reduction of weight was 0.23 %.Singh and Nataraj [9] studied the performance of plunger pump at various crank angles using CFD. The maximum flow rate was observed at crank angle of 300. The volumetric efficiency of the pump using CFD was found to be 91% and slip 8.98%. Samad and Nizamuddin [10] studied flow analysis inside jet pump used for oil wells. The effect of the area ratio and the throat length on the performance of the jet pump has been studied. The result indicated that the efficiency of the jet pump increased up to 20% to 30%. Hubacher and Groll [11] studied crankshaft bearing analysis of a single stage, Semi-Hermetic Carbon Dioxide compressor. The result shows that the frictional losses of the two crankshaft bearings contribute with approximately 19 to 43% to the total frictional losses. Deng et al. [12] carried out analysis of oil discharge rate in rotary compressor by using CFD. The maximum oil circulation ratio 2.85% was observed.few researchers studied effect of piston grooves performance in an axial piston pumps using CFD [2, 5].Some investigator carried out the flow analysis in jet pump using CFD [3, 10]. Fewinvestigators studied the pumping oil distribution by using CFD [4, 12].Few also analyzed the collision contact characteristic of pump [6].The optimization of connecting rod using static and fatigue loading was carried out some of them [7, 8]. Still the researches focus is not concentrated on many aspects of plunger pump. In the present study, the different diameter of discharge chamber is investigated for different pole motor and different plunger positions. II. METHODOLOGY A geometrical model of hydraulic block of reciprocating pump is created in STL format using professional geometric modeler ProEngineer 5.0.Further this model is converted into step format before importing it into ICEM CFD. For this purpose ICEM was used as preprocessor. Figure 1 shows 3D model of hydraulic block of reciprocating pump. This is only fluid passage of reciprocating pump. Hydraulic block contain three parts suction chamber, discharge chamber and cylinder. Figure 1: 3D model of hydraulic block of reciprocating pump A. Mesh Description The computational domain can be discretized using finite volume method. The total number of elements obtained is 491347. The total number of nodes generated is 78424.The Meshed 3D model of hydraulic block of reciprocating pump is shown in Fig 2. Figure 2: Meshing of hydraulic block of reciprocating pump The mesh file is imported in ANSYS FLUENT 14.0 solver software for solution, further analysis and results. The details regarding user inputs such as turbulence model selection, material properties, boundary conditions and analysis solver set-up are given in the subsequent sections. B. Computational Analysis The boundaries and continuum as inlet, outlet and the fluid zone were defined as per the conditions. The geometry as shown in Figure 2 was exported so that it is accessible in Fluent. Fluent is used as a solver for the analysis to be done. model was selected as turbulent model for analysis. Water was selected as working fluid. The Table I gives the information about parameter consider for computational analysis. TABLE I Computational Analysis Pre-processor ICEM-CFD Solver Fluent Post-processor CFD-Post Domain 3D Solver Pressure-Based Time Steady Model RNG k ε model Solution method SIMPLE Fluid Water Near wall treatment Standard wall function Density Ideal gas III. RESULT 2015, IERJ All Rights Reserved Page 2
The values of flow discharge obtained by varying different discharge chamber diameter at different plunger position are investigated.plunger Position 3-12-3 means plunger travel form 3 mm, 12 mm and 3 mm distance from bottom dead center in cylinder of triplex reciprocating pump and same as other plunger positions.the CFD simulation results obtained at different speed and different plunger position in cylinder. Plunger positions are as following. A.Plunger Position 3-12-3 in Cylinder Figure 3 shows the variation of discharge chamber diameter and discharge for 2 pole motor. It is clearly seen from graph that maximum discharge is found to be 1980 lit/hr at discharge chamber diameter 20 mm. The minimum value is found to be 1978.2 lit/hr at discharge chamber diameter 18 mm.as shown in Fig.4 the variation of discharge chamber diameter and discharge is plotted for 4 discharge is found to be 956.88 lit/hr at discharge chamber diameter 18 mm, 24 mm, 28mm and 32 mm. The minimum value is found to be 956.16 lit/hr at discharge chamber diameter 22 mm and 30 mm. Similarly Fig.5 shows the variation of discharge chamber diameter and discharge for 6 discharge is found to be 627.48 lit/hr at discharge chamber diameter 20 mm. The minimum value is found to be 626.04 lit/hr at discharge chamber diameter 22 mm. Figure 6 shows the variation of discharge chamber diameter and discharge for 8 pole motor. It is clearly seen from graph that maximum discharge is found to be 495 lit/hr at discharge chamber diameter 20 mm, 22 mm and 32 mm. The minimum value is found to be 493.2 lit/hr at discharge chamber diameter 22 mm. Figure 4: Variation of Discharge Chamber Diameter Vs Discharge for 4 Figure 5: Variation of Discharge Chamber Diameter Vs Discharge for 6 Figure 3: Variation of Discharge Chamber Diameter Vs Discharge for 2 Figure 6: Variation of Discharge Chamber Diameter Vs Discharge for 8 B. Plunger Position 6-9-0 in Cylinder Figure 7 shows the variation of discharge chamber diameter and discharge for 2 pole motor. It is clearly seen from graph that maximum discharge is found to be 1980.36 lit/hr at discharge chamber diameter 30 mm. The minimum value is found to be 1976.76 lit/hr at discharge chamber diameter 26 mm.as shown in Fig.8 the variation of discharge chamber diameter and discharge is plotted for 4 discharge is found to be 957.24 lit/hr at discharge chamber diameter 30 mm. The minimum value is found to be 955.44 lit/hr at discharge chamber diameter 18 mm. Similarly Fig.9 shows the variation of discharge chamber diameter and discharge for 6 pole motor. It is clearly seen from graph that maximum discharge is found to be 627.12 lit/hr at discharge chamber diameter 30 mm. The minimum value is found to be 624.4 lit/hr at discharge chamber diameter 18 mm and 22 mm. Figure 10 shows the variation of discharge chamber diameter and discharge for 8 pole motor. It is clearly seen from graph that maximum discharge is found to be 495.36 lit/hr at discharge chamber diameter 20 mm and 22 mm. The minimum value is found to be 494.28 lit/hr at discharge chamber diameter 32 mm. 2015, IERJ All Rights Reserved Page 3
Figure 10: Variation of Discharge Chamber Diameter Vs Discharge for 8 C. Plunger Position 9-6-3 in Cylinder Figure 11 shows the variation of discharge chamber diameter and discharge for 2 pole motor. It is clearly seen from graph that maximum discharge is found to be 1980.36 lit/hr at discharge chamber diameter 26 mm. The minimum value is found to be 1978.28 lit/hr at discharge chamber diameter 24 mm.as shown in Fig.12 the variation of discharge chamber diameter and discharge is plotted for 4 discharge is found to be 956.88 lit/hr at discharge chamber diameter 24 mm. The minimum value is found to be 955.8 lit/hr at discharge chamber diameter 30 mm. Figure 7: Variation of Discharge Chamber Diameter Vs Discharge for 2 Figure 11: Variation of Discharge Chamber Diameter Vs Discharge for 2 Figure 8: Variation of Discharge Chamber Diameter Vs Discharge for 4 Figure 9: Variation of Discharge Chamber Diameter Vs Discharge for 6 Figure 12: Variation of Discharge Chamber Diameter Vs Discharge for 4 Similarly Fig.13 shows the variation of discharge chamber diameter and discharge for 6 pole motor. It is clearly seen from graph that maximum discharge is found to be 627.12 lit/hr at discharge chamber diameter 22 mm and 32 mm. The minimum value is found to be 624.04 lit/hr at discharge chamber diameter 18 mm and 30 mm. Figure 14 shows the variation of discharge chamber diameter and discharge for 8 discharge is found to be 495.36 lit/hr at discharge chamber diameter 22 mm. The minimum value is found to be 494.28 lit/hr at discharge chamber diameter 32 mm. 2015, IERJ All Rights Reserved Page 4
Figure 13: Variation of Discharge Chamber Diameter Vs Discharge for 6 Figure 15: Variation of Discharge Chamber Diameter Vs Discharge for 2 Figure 14: Variation of Discharge Chamber Diameter Vs Discharge for 8 D. Plunger Position 12-3-6 in Cylinder Figure 15 shows the variation of discharge chamber diameter and discharge for 2 pole motor. It is clearly seen from graph that maximum discharge is found to be 1979.28 lit/hr at discharge chamber diameter 24 mm and 28 mm. The minimum value is found to be 1977.48 lit/hr at discharge chamber diameter 26 mm.as shown in Fig.16 the variation of discharge chamber diameter and discharge is plotted for 4 pole motor. It is clearly seen from graph that maximum discharge is found to be 959.04 lit/hr at discharge chamber diameter 28 mm. The minimum value is found to be 955.44 lit/hr at discharge chamber diameter 30 mm. Similarly Fig.17 shows the variation of discharge chamber diameter and discharge for 6 pole motor. It is clearly seen from graph that maximum discharge is found to be 634.32 lit/hr at discharge chamber diameter 18 mm. The minimum value is found to be 622.04 lit/hr at discharge chamber diameter 30 mm. Figure 18 shows the variation of discharge chamber diameter and discharge for 8 pole motor. It is clearly seen from graph that maximum discharge is found to be 497.56 lit/hr at discharge chamber diameter 26 mm. The minimum value is found to be 493.56 lit/hr at discharge chamber diameter 24 mm. Figure 16: Variation of Discharge Chamber Diameter Vs Discharge for 4 Figure 17: Variation of Discharge Chamber Diameter Vs Discharge for 6 2015, IERJ All Rights Reserved Page 5
Figure 18: Variation of Discharge Chamber Diameter Vs Discharge for 8 IV. CONCLUSION This paper present results from CFD simulation of hydraulic block of reciprocating pump. For 2 pole motor the maximum discharge is found to be 1980.36 for discharge chamber diameter 26 mm at plunger position 9-6-3.The minimum value is found to be 1976.76 lit/hr for discharge chamber diameter 26 mm at plunger position 6-9-0. For 4 pole motor the maximum discharge is found to be 959.04 lit/hr for discharge chamber diameter 28 mm at plunger position 12-3-6. The minimum value is found to be 955.8 lit/hr for discharge chamber diameter 20 mm and 22 mm at plunger position 6-9-0. For 6 pole motor the maximum discharge is found to be 634.32 lit/hr for discharge chamber diameter 18 at plunger position 12-3-6. The minimum value is found to be 622.08 lit/hr for discharge chamber diameter 30 mm at plunger position 12-3-6. For 8 pole motor the maximum discharge is found to be 497.52 lit/hr for discharge chamber diameter 26 mm at plunger position 12-3-6. The minimum value is found to be 493.2 lit/hr for discharge chamber diameter 28 mm at plunger position 3-12-3. ACKNOWLEDGEMENT The first Authors wish to thanksdampf-kolben, Pune and Department of Mechanical Engineering, STES Sinhgad College of Engineering, Pune for necessary support. REFERENCES [1] Y. Y. Tsui and S. L. Lu, Evaluation of the performance of valvelessmicropump by CFD and lumped system analyses, Sensors and Actuators, vol.148, Issue 1, pp. 138-148, 2008. [2] S. Kumar and J. M. Bergada, The effect of piston grooves performances in an axial piston pump via CFD analysis, International Journal of Mechanical Sciences, vol. 66, pp. 168-179, 2013. [3] J. Fan, J. Eves, V. V. Toropov, N. Kapur, D. Copley and A. Mincher, Computational fluid dynamic analysis and design optimization of jet pump, Computers and Fluids, vol. 46, Issue 1, pp. 212-217, 2011. [4] M. C. Alves, J. R. Barbosa and A. T. Prata, Analytical and CFD modeling of the fluid flow in an eccentrictube centrifugal oil pump for hermetic compressors, International Journal For Refrigeration, vol. 1, Issue 7, pp. 1905-1915, 2013. [5] S. Kumar, J. M. Bergada and J. Watton, Axial piston pump grooved slipper analysis by CFD simulation of three dimensional NVS equation in Cylinder Coordinates, Computers and Fluid, vol. 38, Issue 3, pp. 468-663, 2009. [6] J. Pei, C. Hai, M. Lv, X. Huang, K. Shen and K. Bi, Collision Contact Characteristics for reciprocating pump using FEA and experiments, Advances in Mechanical Engineering, Volume 2013. [7] A. Kumar, K. Grover and B. Budania, Optimization of Connecting Rod Parameters using CAE Tools, International Journal of Latest Treads in Engineering and Technology, vol. 1, Issue 3, pp. 98-104, 2012. [8] O. Parkash, V. Gupta and V. Mittal, Optimizing the Design of Connecting Rod under Static and Fatigue Loading, International journal of research in Management, Science and Technology, vol. 1, Issue 1, pp. 39-43, 2013. [9] R. R. Singh and M. Nataraj, Study on Performance of Plunger Pump at Various Crank angle using CFD, Engineering Science and Technology: An International Journal, vol. 2, Issue 4, pp. 549-553, 2012. [10] A. Samad and M. Nizamuddin, Flow Analyses Inside Jet Pumps Used for Oil Wells, International Journal of Fluid Machinery and Systems, Vol.6, Issue. 1, pp. 1-10, 2013. [11] B. Hubacher and E. Groll, Crankshaft Bearing Analysis of a Single-Stage, Semi-Heremetic Carbon Dioxide Compressor, International Compressor Engineering Conference, 2004. [12] L. Deng, S. Liang, Q. Liu, J. Wu and J. Xu, CFD Analysis of Oil Discharge Rate in Rotary Compressor, International Compressor Engineering Conference, 14-19 July 2012 at Purdue University, West Lafayette, INDIANA, USA. 2015, IERJ All Rights Reserved Page 6