不同入射角度平板气膜冷却的数值模拟

Numerical Simulations of Flat Plate Film Cooling Using Respectively Different Injection Angles

利用RNG k-g湍流模型对斜圆柱孔不同角度入射气膜冷却进行了流动和传热的数值模拟。计算结果表明,在气动方面减小入射角度可以使冷气的射流核心更贴近壁面,但同时明显增大了壁面附近的气流速度;传热的影响也是两方面的,减小入射角度虽然可以显著地提高冷却效率,但同时也明显地增大了换热系数,最终的冷却效果取决于在实际工作状态下的底面热负荷。对于气膜冷却情况,25°入射和45°入射在总体冷却效果上都不如35°入射。

Film cooling with different injection angres was numerically simulated to investigate its flow and heat transfer characteristics, based on RNG κ-ε turbulent model. The results suggest that reducing injection angle can make the core of coolant air closer to the wall, but at the same time, accelerate the velocity of the air close to the wall evidently. The effects on the heat transfer have two sides, and the film cooling effectiveness could be increased obviously by decreasing injection angle, and the heat transfer coefficient increase remarkably at the same time. The actual cooling effect is determined by the wall thermal loads. In the cases of this thesis, the total effects of injection angle 35° is better than that of injection angles 25°and 45°.