Modern compressors are characterized by high pressure ratios, high efficiency, and low weight. To meet these requirements, compressors are operated in the transonic flow range. The flow field of transonic compressor is complex. Shock waves, mixed subsonic and supersonic flow regions, and shock-boundary layer interactions exist simultaneously. Therefore, even small disturbances, such as variations in relative humidity, can significantly affect aerodynamic performance.
To examine the effect of relative humidity on the aerodynamic characteristics of transonic compressors, a transonic linear cascade with varying relative humidity has been designed, built, and tested. Aerodynamic characteristics of cascades such as loading distributions, loss coefficient, and deviation angle have been measured for varying relative humidity. The corresponding loss generation mechanisms have been numerically investigated.