涡轮叶片吸力面上收敛缝形孔气膜冷却对叶栅气动损失的影响

 运用RNG湍流模型对具有气膜冷却的涡轮叶栅通道内部的三维流场进行了数值模拟，分析在叶栅通道主流入口雷诺数Re=4×105~6×105和二次流吹风比M=0.5~3.0范围内，沿吸力面3个典型弦向位置处(分别对应叶栅通道喉部上游、喉部和喉部下游)开设收敛缝形孔对叶栅通道损失系数的影响。计算结果表明：冷气喷射仅对孔附近区域的压力系数产生影响；位于喉部上游位置收敛缝形孔的能量损失及总压损失系数最低，大部分工况中位于喉部下游位置收敛缝形孔的损失系数最高；与圆形孔相比，位于喉部上游位置收敛缝形孔既具有好的冷却效率又具有低的损失系数。

Numerical Investigation on Aerodynamic Loss of Turbine Cascade with Converging Slot Hole Film Cooling at Suction Surface

The three-dimensional turbulent flow in a turbine cascade with blade film cooling is numerically investigated using a RNG turbulence model under different Reynolds numbers ranging from 4×105 to 6×105 and blowing ratios ranging from 0.5 to 3.0. The influence of the converging slot hole location at the blade suction surface (corresponding to the upstream of the throat, the cascade throat and the downstream of the throat) on the aerodynamic loss of the turbine cascade is investigated. Results show that the injection from the converging slot holes has effect only on the pressure coefficient distribution near the film cooling holes. The kinetic loss and total pressure loss induced by the injection from the film holes located at the upstream of the throat are lower than those induced by the other two locations, while the aerodynamic loss coefficients corresponding to the downstream of the throat location are the largest in most cases. Compared with cylindrical holes, the converging slot holes at the upstream of the throat exhibit both higher cooling effectiveness and lower aerodynamic loss coefficient.