Experimental investigation of an active control casing treatment of centrifugal compressors

This paper presents an experimental investigation of stability enhancement of a centrifugal compressor using an Active Control Casing Treatment (ACCT) system. In order to evaluate the effect of ACCT structure on the stability enhancement of centrifugal compressor, experiments were performed at different rotational speeds and various numbers of injection holes and mass flow of injected air by means of the centrifugal compressor test rig with a maximum rotational speed of 15,000 rpm. The experimental results show that the stable working range of centrifugal compressor was extended by 32.73% with injection of 4.5% of design mass flow at an operating speed of 10,586 rpm and by utilizing ACCT with 4 holes. It was found that the enhancement ability increases with the decrease in rotating speed and the injection of 4.5% of design mass flow. The pressure ration of the centrifugal compressor with ACCT was increased due to added momentum of injection air. The pressure ratio of the centrifugal compressor with 16 holes ACCT could be increased by about 1.72% at different mass flow of air injection when the rotational speed was 10,586 rpm.