ターボチャージャー用遠心圧縮機の高性能化設計

（ケーシングトリートメント内ガイドベーンの多目的最適化）

抄録

A high-pressure ratio and a wide operating range are highly required for turbochargers in gasoline/diesel engines. Recirculation flow type casing treatment is effective device for flow range enhancement in centrifugal compressors. Two ring grooves on the suction pipe and the shroud casing wall are connected by the annular passage, and the stable recirculation flow is formed at small flow rate conditions. It is well known that the recirculation flow type casing treatment has following advantages. (1) low energy fluid is successfully sucked out from the downstream groove located near the throat of a rotating impeller, (2) flow incidence is reduced because of that recirculation flow merges with the incoming main flow upstream of impeller inlet. In the present study, the recirculation flow type casing treatment with guide vane is applied to the high speed centrifugal compressor for turbo chargers, in addition, global optimization has performed to find out the optimized shape of the guide vane. It is found that the optimized guide vane has a possibility to reduce an excessive pre-whirl without deteriorating the adiabatic efficiency.