Numerical Analysis of Flow Phenomena in a Centrifugal Pump Impeller of Low Specific Speed

This paper aims to provide a numerical method approach to centrifugal pump manufacturers in Pakistan. Nowadays Computational fluid dynamics (CFD) is widely used to investigate the flow through turbomachines. In this research, centrifugal pump impeller of low specific speed ( Nq=10.5) is numerically investigated to study the flow phenomena and achieve better hydraulic performance through parametric analysis. The shear stress transport (SST) turbulence model is employed to solve 3-D steady RANS equations using CFD solver CFX (ANSYS). The volute hydraulic losses are calculated by loss coefficients predicted by Gulich [1] using Engineering Equation Solver (EES) program. The CFD results show the trend validated with the test data. Two design parameters blade wrap angle and outlet blade angle are considered as design parameter which greatly affect the hydraulic performance (head and efficiency). Additionally, a three-dimensional Rayleigh-Plesset model is also applied to investigate the cavitation (two-phase) flow inside the pump. The inlet blade angle is chosen as a design parameter to resist the cavitating flow inside the pump.