气膜孔倾角对层板隔热屏冷却性能影响

Effects of Film Cooling Hole Angles of Inclination on Cooling Performance of Lamilloy Heat Shield

关键词:  层板隔热屏  气膜冷却  气膜孔  倾角  加力燃烧室

Key words:  Lamilloy cooled heat shield  Film cooling  Film cooling hole  Angle of inclination  Afterburner

摘要:

为了获得气膜孔倾角对层板隔热屏(冲击/发散复合冷却隔热屏)冷却性能的影响规律，基于加力燃烧室真实工况，对0°到90°范围内的十种不同气膜孔倾角的层板隔热屏进行了三维流热耦合数值模拟研究，得到了层板隔热屏冲击壁面Nu数、层板隔热屏气膜冷却表面的冷却效果、层板隔热屏冷流体热负荷及气膜孔流量系数的变化规律。结果表明，气膜孔倾角的变化对冲击壁面Nu数的影响较小；气膜冷却表面的综合冷却效果随气膜孔倾角的增大而减小，15°倾角模型比10°倾角模型的平均综合冷却效果降低2.8%；单位面积冷流体热负荷随气膜孔倾角的增大而增大，最小值比最大值低30.7%；气膜孔倾角对层板隔热屏平均流量系数的影响不大，但上游气膜孔的出流会对下游气膜孔的流量系数产生影响。

Abstract:

In order to obtain the effects of film cooling holes angle of inclination on cooling performance of lamilloy cooled heat shield(impingement/effusion cooled heat shield)，a series of three-dimensional numerical simulations with fluid/heat conjugated computational method were conducted under a real working condition of an afterburner by ten configurations of lamilloy with film cooling holes of varying angles of inclination(α=0°～90°). Change laws of Nusselt number of impinged surface，cooling effect of film cooled surface，coolant heat load and discharge coefficient of the lamilloy have been obtained. Results show that the effect of changing the inclination angle of film cooling holes on Nusselt number of impinged surface is slight，the overall cooling effect decrease with the increase of angles of inclination，the value of 15° model lower 2.8% than 10° model. The coolant heat load increase with the increase of angle of inclination with the minimum value lower 30.7% than the maximum. The average discharge coefficient of all holes is only slightly affected by the angles of inclination but the discharge coefficients of downstream holes are affected by the upstream holes.