采用数值模拟的方法,研究了发动机工作条件下涡轮转子叶片压力面异型气膜孔的冷却特性,分析了吹风比和旋转雷诺数对气膜冷却的影响.结果表明:旋转条件下,气膜射流受离心力和哥氏力作用朝叶尖方向发生偏转,射流涡结构发生改变;随着旋转雷诺数增大,气膜射流向叶尖的偏转量逐渐增加,展向冷却均匀性提高,展向平均冷却效率略有提升;同一转速下扇形孔和收敛缝型孔能有效抑制气膜分离,展向平均冷却效率沿下游单调变化,随吹风比增加而升高,吹风比越小气膜射流向叶尖偏转越明显;旋转条件下,扇形孔与收敛缝型孔射流较圆孔射流仍有明显的冷却优势.
Numerical simulations were conducted to investigate the shaped-hole film cooling on the pressure side of a turbine rotor under engine operating conditions, including the effects of blowing ratio and rotational Reynolds number. Results showed that the film jet was deflected towards the blade tip subjecting to the combined influences of centrifugal force and Coriolis force under rotational conditions, due to the change of the film vortex structure. The film jet was deflected towards the blade tip more sharply with the increase of rotational Reynolds number. The laterally-average cooling effectiveness slightly improved owing to more uniform film coverage. In the same rotational speed, the fan-shaped hole and console hole enabled to effectively restrain the film separation with high blowing ratios compared with the cylindrical hole. The laterally-average cooling effectiveness monotonously decreased downstream and increased with the blowing ratio. Besides, the film jet bent to the tip more notably with a small blowing ratio. As a result, the fan-shaped hole and console hole still have a pronounced advantage over the cylindrical hole under rotational conditions.