The outlet conditions of supersonic compressor rotors designed for very high total pressure ratios can be highly supersonic (impulse rotors). Then the following stator blade row has to build up high static pressure ratios at supersonic inlet conditions. This paper describes part of a research work which should answer, if it is at all possible to realize such high static pressure ratios in a cascade. Cascades with convergent-divergent blade passages were designed and optimized by boundary layer calculations. In a first step no flow turning was incorporated in the blade sections. A three-shock-type cascade was found to be an optimum design The wind tunnel measurements resulted in static pressure ratios of the order of 6 and total pressure ratios of 0.77 at inlet Mach numbers of 2.2. In a second step the flow turning to axial direction was realized. For that two types of cascades were built and tested. One was a tandem type cascade and the other a single row cascade. The experiments at inlet design conditions resulted in static pressure ratios of the order of 6.5 and total pressure ratios of 0.72.

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