The Aerodynamic Design And Analysis Of Couter-Rotating Compressor's Shock-in Impeller

Two basic factors determine the energy transfer to the fluid in axial flow compressors: The circumferential speed and the turning of the flow. Increasing the workload per compressor stage to the limits and reducing stage count and weight of the whole component have been driving factors in jet engine development.By analyzing the traditional supersonic compressors, Rampressor and supersonic inlets the design and analysis of a shock-in type supersonic impeller, which is used in two-stage, vaneless, counter-rotating supersonic compressor, is presented in this paper. The configuration consists of a high tip speed(450 m/s) non-aspirated rotor, followed by a counter-rotating high tip speed (540 m/s) aspirated rotor. The compressor nominal design objectives were a peak total pressure ratio over 10:1 and adiabatic efficiency above 80%. The rotation direction of the second rotor enables the first rotor's blade loading above conventional limits; the peak total pressure ratio of the first rotor is about 2.6. The peak total pressure ratio of the second rotor is about 4.0, and the type of the second rotor reduces the shock loss efficiently. The aspiration of the compressor does not only control the viscous boundary layer loss, but also increase the static pressure ratio of the second rotor.In the paper, the conception of 2D shock-in type cascade was simulated with CFD method, and tested in a shock tube facility. Design intent and CFD predictions are strongly supported by the test results. After 2D investigation, 3D design and analysis of the shock-in type impeller are followed. The relative inlet March number of the new shock-in type rotor is 2.0. Different from traditional supersonic axial compressors, the new rotor is designed for a slight turning in the rotor blade passage with a normal shock at the end of the passage shock system. The March number at the outlet of the rotor is about 0.3～0.7, and the flow angle is about 60°～70°. The static pressure rise across the rotor is up to 4.0; the total pressure recover rate of the rotor is about 0.82. We also design a Counter-Rotating Compressor with a shock-in type HP impeller. The total-pressure ratio of the Counter-Rotating Compressor reach 10, and its static pressure ratio is about 8.As the conclusion, the Shock-in Type Counter-Rotating Compressor is a simple, cheap and efficient compressor. It is aggressive in the development of high performance jet engine.