The unsteady performance of a centrifugal compressor with different diffusers

Abstract

Unsteady flow in turbomachinery may be due to turbulence, wakes (rotor-stator interaction), inlet distortion, rotating stall or surge. It is undesired, because it may lead to narrow operation range, poor efficiency and blade failure due to vibration. Four low solidity vaned diffusers (LSVDs) together with one conventional vaned diffuser and two vaneless diffusers were tested downstream of the same impeller for the purpose of understanding the unsteady performance (stall and surge characteristics) of each diffuser and the performance relative to each other. This paper is a complementary paper to previous work where the design and overall and component performances of eight LSVDs have been reported.