V肋对尾缘劈缝气膜冷却特性的影响

The influence of the V-shaped ribs on the film cooling characteristics of the trailing-edge cutback is studied using the pressure-sensitive paint technology and the transient thermochromic liquid-crystal technology. The distributions of the film cooling effectiveness and heat transfer coefficients on different cutback surfaces with varying V-shaped rib widths at varying blowing ratios are obtained. The heat flux ratio is adopted to evaluate and compare the overall cooling performance of the turbulated cutback surfaces with V-shaped ribs. The experimental results show that the addition of V-shaped ribs has an adverse effect on the film coverage on the unexpanded surface. At low blowing ratios, the rib width has no significant effect on the area-averaged film cooling effectiveness. For the cases with the same rib width, the film cooling effectiveness of the unexpanded surface is always higher than that of the expanded surface. The effect of the V-shaped rib width on the heat transfer enhancement of the trailing-edge cutback is not obvious. The V-shaped ribs exhibit a stronger heat transfer performance on the unexpanded surface than that on the expanded surface. Compared with the primeval trailing-edge cutback, the net heat flux reduction of the case with V-shaped ribs can significantly increase by a factor of 6.9%-26.6%, and the width has no significant effect on the wall heat flux. At low blowing ratios, it is advisable to use V-shaped ribs on the unexpanded surface, while unnecessary to consider the shape of the trailing-edge cutback at high blowing ratios.