Investigations of an Axial Flow Compressor with Tandem Cascades

In axial flow compressors with high degrees of reaction the transfer of energy can be increased by using suitable tandem cascade arrangements. The application of multistage tandem cascade systems therefore allows savings in constructional length and blading and thus a very compact compressor design. Therefore a four-stage tandem cascade compressor with 100 percent reaction was built. To determine the operating behavior of the machine, the compressor characteristic on speed control was measured. For optimization and further development of this compressor the characteristics on adjustment of all stator blade rows and speed control were measured. To allow the behavior of the stator blade rows and tandem cascade wheels to be assessed, the channel flow in the axial gaps behind selected wheels was measured. The tandem cascade compressor, its layout and the results of experimental investigations are presented and discussed.