206Numerical Simulation of Crude Oil Fluid Flow in a Water Centrifugal Pump and Flow Investigation at Design Point and Off-design Conditions


Abstract:

This article presents a numerical investigation of fluid flow in one of the centrifugal pumps of pump-Iran corporation. A computational fluid dynamics (CFD) analysis is performed by using the CFX software for a wide range of volumetric flow rates for two different rotor speeds of 1450 rpm and 2900 rpm and the numerical results of water are validated against measured values of head and total efficiency with an overall acceptable agreement. The obtained results have been obtained for crude oil as diagrams of head and total efficiency as functions of volumetric flow rate and other variables and compared with results of water. Numerical results show that the absolute pressure on blade surfaces for crude oil is 705 kpa less than when using water. The absolute pressure differences between inlet and outlet of impeller and spiral volute for crude oil are comparatively less than those amounts in comparison with water. Also by increasing the angular velocity of rotor, it was observed that high levels of turbulence intensity are transmitted from outlet pipe bending to the impeller outlet at volumetric flow rate of 30 m3/h that causes the efficiency reduction and also high levels of turbulence intensity for crude oil are less than those amounts in comparison with water within impeller area. Finally, to represent a pump impeller head curve for crude oil over the overall operating range of the pump, a second order polynomial equation was fit to numerical data. 

Keywords: Numerical simulation, centrifugal pump, characteristic curve, Turbulence intensity, crude oil

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