Experimental investigation of the casing treatment effects on steady and transient characteristics in an industrial centrifugal compressor

► A new casing treatment method is proposed and applied in an industrial compressor. ► Surge margin is improved by 10%Qdesign with negligible decrease in efficiency. ► Bleeding flow occurs near surge side and bypass flow occurs near choke side. ► Modal stall occurrence moment is delayed by use of casing treatment. ► Modal stall cells travels a little faster by use of casing treatment.