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通过数值模拟的方法,揭示了整级涡轮叶片在旋转状态下的气膜冷却特性。计算采用六面体结构化网格,湍流模型选用k-ε两方程模型。计算中,主流进口雷诺数为7.7×10~4,旋转数分别为2.092、2.324和2.448,吹风比分别为0.5、1.0、1.5和2.0,冷却工质采用空气,对应射流主流密度比为1.03。计算结果与之前的实验结果进行了比较,并着重分析了旋转附加力的作用机理。结果表明:压力面上,气膜轨迹向高半径方向偏转,其偏转程度随吹风比的增大而减弱,随旋转数的增大而加强;气膜覆盖面积和冷却效率随吹风比的增大而增大,随旋转数的增大而减小。
Through the numerical simulation method, the gas film cooling characteristics of the whole-grade turbine blades under the rotating condition are revealed. Calculated using hexahedral structured grid, turbulence model selection k-ε two-equation model. Calculation, the mainstream inlet Reynolds number of 7.7 × 10 ~ 4, the number of revolutions were 2.092,2.324 and 2.448, hair blowing ratio was 0.5,1.0,1.5 and 2.0, respectively, the cooling medium using air, the corresponding jet mainstream density ratio of 1.03. The calculation results are compared with the previous experimental results, and the mechanism of the additional action of rotation is analyzed emphatically. The results show that on the pressure surface, the trajectory of the gas film deflects to a high radius, and its deflection decreases with the increase of the blowing ratio and strengthens with the increase of the rotating number. The coverage of the film and the cooling efficiency increase with the blowing ratio But increases, decreases with the increase of the number of revolutions.