涡轮叶片前缘气膜冷却数值模拟

对具有双排气膜孔的涡轮叶片前缘进行了气膜冷却数值模拟,在吹风比M为0.5,1.0的情况下得到了相邻两排孔的流场和气膜冷却效率的分布规律,并将计算结果与实验进行了对比分析.结果表明:①在不同的吹风比下,两排孔的冷气射流运动非常复杂,冷却效率沿流向的分布都是非线性的;在M为1.0时,25°的小角度喷射气膜冷却效果较好.②利用两层κ-ε湍流模型比传统的κ-ε湍流模型数值预测的精确度高,可较好地模拟叶片前缘的气膜冷却特性.

Numerical simulation of film cooling in leading edge of turbine blade

Film cooling characteristics of a turbine blade leading with two rows cooling orifices is investigated using a three-dimensional finite volume method and multi-block technique. The present study received flow and heat transfer characteristics about two rows of coolant at turbine blade leading. Furthermore, this paper calculated film cooling effectiveness when the injection angle was 25°,35°,45°and 65°.Computed results were presented in the form of adiabatic effectiveness contours on the blade surface and compared with experimental. It was found that the strength and the size of vortex could be reduced by decreasing injection angle. It was also established that the best cooling effectiveness is provided by a small injection angle of 25°to the stagnation line. It was shown that two-layer models was better than commonly models, but it overpre-dict or underpredict the lateral averaged film cooling effectiveness of gas turbine blades through compared with experimental results.