AN EXPERIMENTAL STUDY OF 3-D FLOW IN A CASCADE

An experimental investigation of three dimensional flow in a cascade has been accomplished by means of flow visualization and detailed measurements,and also compared with the predictions of fully three dimensional inviscid flow calculation.The experimental measurements of the three dimensional flow in a highly cambered compressor cascade with nonplanar end wall reveal the distributions of flow parameters on blade surfaces and the whole flowfield in cascade channel.In comparison with the two dimensional cascade measurements for the same blade section,the results show that the influence of the end wall shape changing on the flow is not confined to the vicinity of end walls,and can extend to the whole field when the aspect ratio of blading is small.The comparison between the experimental data and the computational results confirms that the inviscid flow calculation can predict the major features of three dimensional flow in cascades.The flow visualization reveals the formation and development of vortex systems in the cascade passage,end wall and corner regions,which serve as a visualized information to understand the phenomena of complicated secondary flow in cascades.The experimental measurements provide a reliable basis to perfect the flow models,to investigate the mechanism of spanwise mixing in a cascade and to testify the capabilities of fully three dimensional cascade flow calculation methods.