单入口-双出口孔射流流量系数研究

摘要

In order to investigate the flow resistance of the one inlet and double outlet hole used on the blade of the aero-engine,the experiments of the discharge coefficients with various orientation angles of the branch hole were conducted in the low speed wind tunnel.Blowing ratios changes from 0.2 to 2.0.The Reynolds numbers based on the mainstream velocity and the diameter of the holes are 6200,9300 and 12400 respectively.The results shows that the discharge coefficients of the one inlet and double outlet holes which have the orientation angles of 45°and 90°are larger than those of the other shaped holes up to 15%.Not the Reynolds numbers and orientation angles,but the changes of blowing ratios,are the dominant reasons of the change of the discharge coefficients at low blowing ratios.The changes of blowing ratios,Reynolds numbers and the orientation angle of the branch holes have considerable effect on the discharge coefficients at high blo-wing ratios.The one inlet and double outlet holes with 45°orientation angles is necked to be the optimal one based on the discharge coefficients and cooling effectiveness.%为了探讨单入口-双出口孔内流阻特性，试验研究了不同次孔方位角下该孔的流量系数。吹风比变化范围为0．2到2．0，基于通道入口主流速度和气膜孔直径的雷诺数为6200、9300和12400。结果表明：次孔方位角45°和90°的单入口-双出口孔流量系数大于其他孔型流量系数，最大增幅为15％；低吹风比时，吹风比变化是引起流量系数变化的主要原因，而主流雷诺数和次孔方位角变化对流量系数几乎没有影响；高吹风比时，吹风比、雷诺数和次孔方位角的变化对流量系数都有一定影响。综合考虑流量系数和文献中冷却效率数据，得出次孔方位角为45°的单入口-双出口孔为最优孔型。