Numerical Investigation On Compound Angle Film Cooling Of Turbine Blade

Enhancing the temperature of gas turbine's inlet is one of the key technologies to improve the efficiency of the gas turbine, and the requirement of high temperature support of the blade is much higher than before. As a result, investigating on flow and heat transfer performance of blade's film cooling is important to protect the blade effectively and design the gas turbine.Basing on SIMPLEC algorithm and discretizing the control equation in finite volume method, Realizable k-εturbulence model is applied to simulate the injection behaviors from two rows of film cooling holes with opposite orientation angles. Six film cooling hole arrangements were considered including inline and staggered ones. The temperature is 313 K for the main flow and the 293K for the jet flow. And three blowing ratios of 0.5, 1.0, and 2.0 were studied. The conclusions are as follows: At the blowing ratio of 0.5, the injection is centered near film cooled surface irrespective of hole configuration to show high film cooling effectiveness. With the inline configuration, unlike other configurations, the injection is still well attached to the wall with the help of the downwash flow formed at the hole exit. Because of the hole-to-hole space between the fifth hole-row and the sixth hole-row was even close, the jet is not very uniform, but the cooing efficiency of the area near the hole is pretty high, and the film cooling is formed between the hole. In the present study, the highest film cooling efficiency is obtained at the blowing ratio of 0.5 for the third hole-row, for the first hole-row, however, the blowing ratio of 1.0 yields better protection beyond x/d=2.0.Then we simulated the temperature distributing of the pressure and suction wall of a stationary gas turbine at different blowing ratio of M=0.5,M=1.0 and M=1.5 and the mainstream temperature is 293K , while the jet hole of the leading edge has compound angle. The compound angle areα=30°,β=45°,α=90°,β=45°andα=135°,β=45°. The cooling efficiency was also analyzed in typical conditions. The conclusions are as follows: Firstly, with the same compound angle and different blowing ratio, the change trend of the cooling efficiency curve of the pressure and suction wall is consistent; Secondly, the compound angle jet of the leading edge influenced the cooling efficiency of the suction wall,ηgoes up when the blowing ratio is increased and when the compound angle of the leading edge isα=30°,β=45°, the cooling efficiency of the pressure wall is enhanced as the blowing ratio is increased. However, the cooling efficiency of the pressure wall is reduced as the blowing ratio is bigger when the compound angle of the leading edge isα=90°,β=45°andα=135°,β=45°.