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采用大涡模拟,考察了旋转影响气膜冷却的物理机制。参考实验模型,用带有30°倾斜圆柱孔的平板模拟涡轮转子叶片的吸力面,冷气出口雷诺数为1300,冷气和主流的吹风比为0.5,计算了静止和旋转数为0.2两种条件下的流动和换热,全面展示了旋转对平均流场、涡量、湍流结构和壁面温度分布的影响,并由此对实验现象进行了解释。结果表明,旋转使气膜孔下游的对转涡对产生不对称性;旋转引发的哥氏力使气膜冷却流场中的发夹型漩涡结构向高半径方向偏移,引起涡量分布的改变;旋转破坏了发夹涡的连续性,减少了对主流的卷吸和主流传递给冷气的热量,从而提高了冷却核心区的冷却效率,与实验中观察到的现象一致。
Large eddy simulation is used to investigate the physical mechanism by which the rotation affects the film cooling. With reference to the experimental model, the suction side of a turbine rotor blade was simulated by a flat plate with a 30 ° inclined cylindrical hole. The Reynolds number of the cold air outlet was 1300, and the air-blow ratio was 0.5. The static and rotational numbers were calculated under 0.2 The effects of rotation on the mean flow field, vorticity, turbulent structure and wall temperature distribution are fully demonstrated. The experimental phenomena are explained. The results show that the rotation causes asymmetry of the pairwise vortex pairs downstream of the film hole. The rotationally induced Coriolis force causes the hairpin-type vortex structures in the film cooling flow field to shift toward the high radius, causing the vorticity distribution Change; Rotate destroying the continuity of hairpin vortex, reducing the mainstream of the entrainment and the mainstream of heat transfer to the air-conditioning, thereby enhancing the cooling core cooling efficiency, consistent with the observed phenomenon.