Performance Characteristics and Internal Flow Analysis of Centrifugal Pump

Abstract

For the cost-effective design of centrifugal pump thorough understanding of internal flow behaviour in the different components is necessary which may be subjected to unsteadiness, turbulence along with two-phase characteristic. Computational Fluid Dynamics (CFD) is the present day state-of-the-art technique for fluid flow analysis in hydraulic machines. This paper presents an internal flow analysis of single stage end suction centrifugal pump (head: 22 m, discharge: 220 m3/hr) using Fluent software. The 3D computational model was discretized using unstructured tetrahedral grid and steady state simulations were performed using Reynolds Averaged Navier Stokes equations along with standard k-ε turbulence model. Casing was considered in stationary reference frame and impeller was defined in moving reference frame. The performance was predicted in the wide range of discharge at six operating points. The flow was analysed in terms of velocity and pressure contours, velocity vectors and path lines at part load, rated and over rated discharge. The comparison of numerical and experimental results showed 2-8% deviation in head, power and efficiency which may be due to negligence of friction, mechanical and volumetric losses. Maximum efficiency obtained with CFD and experiments was found to be 87.54% and 85% respectively, which shows very good agreement between the two approaches.