Superposition method for multi rows of a film cooling hole on a turbine stationary vane surface

Abstract

The superposition characteristics of film cooling effectiveness in the multi rows of shaped film cooling holes are investigated experimentally. It appeared from the experiments that the superposition characteristics are realized at a small blowing ratio of M=0.5. However, the film cooling effectiveness that is estimated by a method presented by Seller is approximately 20% higher values than that of the experimental value at blowing ratio of M=1.0. And furthermore, it becomes clear that the estimated film cooling effectiveness is approximately 100% higher than that of the experiment at M=2.0. On the other hand, by the experiment using a lowspeed cascade test facility, it becomes clear that the superposition of the film cooling effectiveness blowing through two rows of shaped film cooling hole is established on the pressure surface of a stationary turbine vane because of a strong mixing motion of film cooling air and main stream. On the contrary, it became clear that the estimated value showed approximately 30% lower value compared with the experimental value on the suction surface of the model turbine vane.