Influences of diffuser types on the performances of centrifugal compressor

Numerical study on a turbocharging centrifugal compressor with vaneless, vane and tandem vane diffuser are carried out to investigate the influences of diffuser types on the compressor performances. Results show that low solidity vane diffuser can increase the compressor efficiency near design point with certain loss in stability range. With the use of tandem diffuser, efficiency and stability range can be further improved upon vane diffuser. Results also indicate that under off-design point near surge, large flow attack angle leads to big separation and flow losses, which can be effectively improved by variable diffuser. These results can supply theoretics for the design and fully adjustable strategy of centrifugal compressor.