Pulsed film cooling on a complete turbine blade: steady, sinusoidal and square injections

The effect of the curvature of the blade and the existence of pulsation in compressor injection air highlights the importance of pulsating flow analysis on a complete turbine blade. Sinusoidal and square pulsed film cooling on leading-edge (LE), pressure and suction sides (PS and SS) of a complete NASA C3X blade is numerically investigated. The performance of film cooling is studied for five blowing ratios from 0.5 to 2.5 at the frequency of 50 Hz and three of the mainstream Reynolds numbers ( Re ). The numerical simulations have been performed by the S S T k - ω model. The results showed that film effectiveness is different for the two considered pulse flows. The most value of averaged film effectiveness is obtained on PS, in which its minimum happens at the LE. For the sinusoidal pulse, the average film effectiveness was almost two times more than the square wave. With increasing the blowing ratio, pulsed film cooling effectiveness is reduced at LE and PS but at SS this trend was reversed. The averaged centerline pulsed film effectiveness on the LE and PS at the blowing ratio of 0.5 and for SS at the blowing ratio of 2.5 was maximum. The effect of mainstream Reynolds number variations on pulsed film cooling had the most effect on PS. At LE and SS, at R e = 74652 , film effectiveness was the most value while at PS for R e = 111978 the largest effectiveness was obtained.