带气膜出流叶片前腔内表面冲击换热数值模拟

采用数值模拟方法对不同雷诺数下静止状态涡轮叶片前腔带气膜孔出流的冲击流动与换热特性进行了研究.分析了叶片前缘冲击流动产生的不同涡团对其内表面换热的作用机理.计算结果表明:相同雷诺数下,叶片前缘内表面气膜孔附近的换热强化比高于通道的平均值.随着雷诺数增加,换热强化比有所提高.冲击流动与通道流动耦合而形成的波浪形涡区,极大地扩展了冲击强化换热区域.气膜孔出流的抽吸作用对冲击流产生影响,进一步扩大了冷却空气在前缘内表面的覆盖范围.气膜腔叶根处纵向截面的涡团阻碍了冷气向叶根方向扩展,降低了冷却效率;而横向截面的涡团则促进冷气与壁面热气的掺混,提升了换热效果. 

Numerical investigation of impingement and heat transfer on inner surface of airfoil former cavity with film holes

Numerical simulations of impingement and heat transfer in a static airfoil former cavity with film holes were performed on conditions at different Reynolds numbers. Flows of the vortex by impingement on heat transfer mechanism was analyzed on the inner surface of leading-edge. The numerical result shows: heat transfer enhancement on the area near film holes is higher than the average value of channel at the same Reynolds number and it increases slightly with the higher Reynolds number. Wavy area of vortex generated by impingement and cross-flow extends the scope of enhanced heat transfer greatly. Suction effect of film holes flow generates an impact on impingement and enlarges the covering area of cooling air on the inner surface of leading-edge furthermore. Vortex in the vertical section of the film chamber root hinders cooling air flowing there and results in a lower cooling efficiency. While vortex in the cross-section promotes the mixing of cold and hot air near the wall with an enhancement in heat transfer.