THE IMPACT OF THE VORTEX DESIGN METHOD ON THE STALL BEHAVIOR OF AXIAL FLOW FAN AND COMPRESSOR ROTORS

摘要

The paper presents comparative studies on low-speed isolated rotors of free vortex design and controlled vortex design (CVD), in order to survey the impact of the vortex design method on the stall behavior of axial flow turbomachinery. The studies are based on 3D laser Doppler anemometer studies and global performance measurements, supplemented with literature data. CVD bladings are characterized by radially outward flow on the suction side due to spanwise changing circulation, and increased near-tip solidity and/or loading. These features were found to increase the near-tip endwall flow blockage and loss at the design flow rate, and to hasten stall. On this basis, it has been concluded that CVD tends to be disadvantageous from the viewpoint of the stall behavior. It was confirmed that forward blade sweep is a remedial strategy for moderating the stall-hastening effects of CVD, while retaining the favorable features of CVD.