前缘射流对涡轮导叶吸力面多排气膜孔冷却特性的影响

为了研究前缘射流对吸力面多排气膜孔下游冷却特性的影响，在跨声速风洞中进行了实验并采用热电偶获得了气膜冷却效率和换热系数。叶栅进口雷诺数的范围为2.0×105 ~ 4.0×105，出口等熵马赫数为0.95，叶栅前的湍流度小于5%。前缘布置6排对冲圆柱孔，质量流量比的范围为2.00% ~ 3.71%，吸力面布置4排圆柱孔，质量流量比的范围为2.02% ~ 3.74%。实验结果表明：在没有前缘射流时，吸力面的气膜冷却效率随质量流量比增大先升高后下降，存在前缘射流时，质量流量比对气膜冷却效率的影响较小。对所有的工况而言，质量流量比增大都提高了吸力面的换热系数。相比于没有前缘射流的工况，前缘射流显著提高了吸力面孔排附近区域的气膜冷却效率并略微降低了换热系数；在吸力面后半段，前缘射流显著提高了换热系数而对气膜冷却效率影响较小。总的来说，前缘射流改善了吸力面孔排附近区域的冷却效果，但是恶化了吸力面后半段区域的冷却效果。

Effects of Leading Edge Injection on the Film Cooling Characteristics of Multirow Cooling Holes on the Turbine Vane Suction Side

An experiment was carried out in the transonic wind tunnel to investigate the effect of leading edge injection on the cooling characteristics downstream of multirow film cooling holes on the turbine vane suction side. The film cooling effectiveness and heat transfer coefficient were obtained by the thermocouples. The inlet Reynolds number of the cascade ranged from 2.0×105 to 4.0×105 and the exit isentropic Mach number was 0.95, the turbulence intensity upstream of the cascade was less than 5%. Six rows of counter-inclined cylindrical holes were provided on the leading edge and the mass flow ratios ranged from 2.00% to 3.71%. Four rows of cylindrical holes were arranged on the suction side and the mass flow ratios ranged from 2.02% to 3.74%. The experimental results show that without the leading edge injection, the film cooling effectiveness on the suction side first increases then decreases with the mass flow ratio increasing, however, the effect of mass flow ratio on film cooling effectiveness is not pronounced in the presence of leading edge injection. The increased mass flow ratio leads to enhanced heat transfer coefficient on the suction side for all cases. Compared with the cases without leading edge injection, the leading edge injection significantly improves the film cooling effectiveness and slightly reduces the heat transfer coefficient in the area near the hole rows on the suction side. In the rear half of suction side, the leading edge injection markedly enhances the heat transfer coefficient, whereas has little effect on the film cooling effectiveness. In summary, the leading edge injection improves the cooling performance in the vicinity of hole rows on the suction side, however, worsens the cooling performance in the rear half of suction side.