Influence of blowing ratio on film cooling of rotating turbine blade

Experimental investigations were carried out to study the rotating film cooling characteristics at different blowing ratios in a 1.5-turbine stage. The mainstream Reynolds number Re_g is 1.6451×10⁵ in the experiment. CO₂ acts as a coolant with mainstream jet density ratio of 1.57. Turbine speed is 475 r/min, and the rotation number is 1.901. The blowing ratio varies from 0.5 to 2.0. By using steady-state liquid crystal method, the results show that: (1) On pressure side, the film cooling efficiency and the film coverage increase, the deflection angle of film trajectory decreases with the increasing blowing ratio. (2) On suction side, the film cooling efficiency and the film coverage first increase and then decrease, the film trajectory has no obvious deflection angle with the increasing blowing ratio. (3) The curvature radius of jet flow affects the adhesion of film on the wall.