主流湍流度对涡轮导叶吸力面W型气膜孔冷却效率影响的实验研究

In order to achieve the film cooling characteristic of W-shaped film holes at different positions on the suction side of a subsonic turbine vane, an experiment was conducted in the short-duration transonic wind tunnel to investigate the effect of blowing ratio and mainstream turbulence intensity on the film cooling effectiveness. Two single row of film cooling holes (SS1 and SS2), are respectively located at 16% and 21% relative arc length on the suction side. The range of inlet Reynolds numbers was 3.0×10⁵~9.0×10⁵ and the range of blowing ratios was 0.5~2.0. The isentropic exit Mach number of the cascade was 0.8. The high and low turbulence intensity was 14.7% and 1.3%, respectively. The experimental results show that: at low turbulence intensity, the film cooling effectiveness downstream of SS1 and SS2 increases first and then decreases with the increase of blowing ratio, and the optimal blowing ratio is BR=1.2 and BR=0.8, respectively. The turbulence intensity has different effects on the film cooling effectiveness of SS1 and SS2, because the states of mainstream boundary layer is different. For SS1, high turbulence intensity makes the core of coolant to move towards the wall surface and improves the film cooling effectiveness at large blowing ratio, however, reduces the cooling effectiveness at small blowing ratio. The influence is weaker as the Reynolds number increases. For SS2, high turbulence intensity increases the cooling effectiveness in the vicinity of the film holes and increases the rate of decay along the flow direction at large blowing ratio, however, significantly reduces the film cooling effectiveness downstream of film cooling holes at small blowing ratio.