Effects of wake-blade interaction upon aerodynamic performance of a turbine linear cascade Part 2: wake-decay characteristics

摘要

This paper demonstrates the detailed measurements of the time-varying flow field downstream of the turbine cascade and the moving bars. Through the measurements using a quasi-X probe, pitchwise distributions of the ensemble-averaged velocity atthe midspan are acquired. These temporal velocity data are transformed into velocity vectors by use of Taylor's frozen model, which also enables the calculation of the vorticity associated with the incoming wakes. The resultant velocity vectors and thevorticity distributions provide clear images of the deformation of the incident bar wakes that are bowed and directed to the suction side of the blade wake. Comparisons between the measurements and correlations of the bar wake decay show that the wakedecay process through the cascade is more gradual than that in the uniform flow field.