CFD analysis of impeller-diffuser interaction in a centrifugal compressor with twisted vaned diffuser

Abstract

The effect of variation of diffuser radius ratio on the performance of a centrifugal compressor stage with vaneless diffuser (VLD), low solidity vaned diffuser (LSVD), and twisted vaned diffuser (TVD) was studied using Computational Fluid Dynamics (CFD). ANSYS CFX software was used in the present study. The diffuser vane was generated by modifying the trailing edge of a cambered aerofoil profile (NACA 2410). The stagger angle was varied from hub to shroud forming a twisted vane diffuser keeping the same leading edge. The present analysis was carried out at a tip Mach number of 0.35. The performance was assessed in terms of stage power coefficient, stage efficiency, total pressure loss coefficient and static pressure recovery coefficient for five different flow coefficients in the diffuser. From the present study, the optimum radius ratio is 1.10 for TVD with the chosen impeller diffuser configuration.