Numerical Experiments on a Centrifugal Pump

Advances in Computational Fluid Dynamics have made it possible to visualize some of features of flow through rotating machines, that are if not impossible, difficult to measure experimentally. Now Industry standard CFD codes are commercially available and are being used by leading industries as a design verification tool. Most of the commercial codes are general purpose, keeping in mind vast application needs. Various turbulence models, numerical schemes and grid types are given as an option for the end user. Appropriate choice of grid, numerical scheme, interfaces and turbulence models are the key parameters that influence the results from CFD software. A centrifugal pump was designed and developed using empirical and optimization tools developed in-house. The flow passages were checked for smooth flow pattern using CFD tools. The pump was manufactured and tested for its performance. The tested performance matched well with predictions within 3% at best efficiency point as regards to efficiency and head. This model was taken to carry out numerical experiments using CFD tools. The entire performance including flow-head-efficiency and cavitation performance in terms of NPSHr requirement was available. Numerical experiments were carried out to study impact of different parameters like numerical scheme, turbulence models, type of interface between stationary and rotating parts. The results from these numerical experiments are presented and discussed in the light of actual test results from laboratory testing.