吹込みノズル装置による遠心圧縮機のサージングの抑制

―高速回転域での吹込みの効果―

抄録

In a centrifugal compressor which is a main component of turbocharger, instability phenomena such as surge and rotating stall occur at low flow rate conditions. These phenomena degrade the performance characteristics of compressor and may damage the compressor system. Nozzle injection system is one of the effective methods to suppress the instability phenomenon and composed of the injection nozzle and the bypass tube. A part of air compressed by the compressor is extracted from the scroll outlet and injected into the impeller inlet by the nozzle installed on the inner wall of suction pipe through the bypass tube. It has been already clarified that the most effective circumferential location of injection was located around the opposite side of the scroll tongue against the rotational axis of impeller. In this study, the effect of the increase of rotational speed on the effect of injection nozzle for the surge suppression was investigated in detail. The results showed that the increase of rotating speed enhanced the effectiveness of nozzle injection system and enlarged the effective circumferential region of the injection nozzle.