Abstract: The shock structure in a transonic compressor with the low aspect ratio of blading is three dimensional. The shock loss of the flow in close proximity to the outer casing is significant. A known weakness of the three dimensional shock loss model of Wennerstrom and Puterbaugh is its treatment of the shock surface in the vicinity of the outer casing. By studying the interaction between shock and the outer casing boundary, an improved model is presented for predicting the shock loss through a transonic or supersonic compressor blade row operating at peak efficiency, which can consider the changes of the shock structure and its strength owing to the interaction of the shock and the outer casing boundary layer. The results using the improved model agree very well with those by the experiment.

Key words: supersonic turbines, three dimensional flow, shockwave interaction, shock wave atten2uation