抄録
In the operation of a centrifugal compressor of turbocharger, instability phenomena such as rotating stall and surge are observed at lower flow rate than that at the designed point. Therefore, it is important to control the onset of instability phenomena to extend the stable operation range of centrifugal compressor to the low flow rate region. In the present study, the control of rotating stall and surge for a centrifugal compressor was tried by using a nozzle injection system in which a part of the flow from the delivery duct was re-circulated to the impeller inlet. The three types of air injection nozzle were used to investigate the effect of nozzle inner diameter on the performance characteristics. In addition, the circumferential position of the injection nozzle was changed in order to examine the relationship between the optimum position and the nozzle inner diameter.
