INVESTIGATION OF THE 3-D FLOW STRUCTURE IN A HIGH-SPEED ANNULAR COMPRESSOR CASCADE FOR TIP CLEARANCE EFFECTS

ABSTRACT The results of an experimental investigation of the flow in a high-speed annular compressor cascade with a hub tip clearance gap and a rotating hub wall are presented. 3-1) flow measuranents are conducted by means of WA and five hole probes. Detailed flow field data are presented at successive axial planes in a blade passage. Blade surface pressure distributions are also used, to support the interpretation of the in-passage measuremans. The features of the clearance flow are captured and discussed Results are shown for two sizes of the tip clearance gap, while relative wall motion is present_ The features of the flow revealed by the present investigation are compared to existing information from low speed studies and it is concluded that the basic physical mechanisms known still prevail for flows which are closer to actual operating compressor flows