Numerical Simulation of Different Turbulence Models in a Compact Return Diffuser

CFD have been became the main method to study the pump inner flow patterns. It is important to understand the differences and features of the different turbulence models. In this paper, the velocity flow fields in a compact return diffuser under multi-conditions are studied by CFD and PIV measurements. In the numerical simulation, three turbulence models are used to solve the steady flow filed using high-quality fine structured grids, which are including SST k-ω model, DES model and SST k-ω model with low-Re corrections. A special test rig is designed to carry out the 2D Particle Image Velocimetry (PIV) measurements, and the PIV results are used to validate the CFD results. The detailed comparison between different turbulence models and PIV results is performed. Velocity flow fields in the diffuser middle section are compared and analyzed under different flow rates. SST k-ω model with low-Re correction give a better results comparing to DES and SST k-ω model, especially have a good predication about the vortex core position under strong part-loading conditions.