Low-Solidity Cascade Diffuser for Transonic Centrifugal Compressor

Abstract

Low-solidity circular cascades, conformally transformed from a high-staggered linear cascade of 0.69 in solidity using double circular-arc vane sections, were applied as a part of the diffuser system of a transonic centrifugal compressor. Performance test results were compared with vaneless diffuser data. Good compressor performances, a wide flow range as well as a high pressure ratio and a high efficiency, superior to those with a vaneless diffuser, were demonstrated. Furthermore, the test circular cascade diffusers demonstrated a good pressure recovery in a wide range of flow angles, even when the inflow Mach number to the cascade was over unity.