流向/周向曲率对加力尾部双层壁隔热屏冷却性能影响

Effects of Flow and Circumferential Curvature Radiuson Cooling Performance of Double Wall Heat Shield of Afterburner Tail

关键词:  曲率半径  双层壁隔热屏  加力燃烧室  冷却效果  冷却气量

Key words:  Curvature radius  Double wall heat shield  Afterburner  Cooling effect  Cooling air flow

摘要:

为了得到流向/周向曲率对双层壁隔热屏冷却性能的影响规律，基于加力燃烧室尾部圆转方双层壁隔热屏弯曲型面的工况条件，建立了两组共6种不同流向曲率半径和5种不同周向曲率半径的双层壁隔热屏冷却模型，采用三维流热耦合数值模拟方法对流向和周向曲率半径对双层壁隔热屏冷却性能的影响进行了研究，得到了双层壁隔热屏气膜冷却表面的综合冷却效果、冲击靶面的Nusselt数Nu、气膜冷却表面的单位面积冷却气量等的变化规律。结果表明，随着正流向曲率半径的增大，综合冷却效果先增大后减小，变化幅度达3.18%，冲击靶面Nu先减小后增大，单位面积冷却气量增大，增大幅度达9.78%；随着负流向曲率半径的增大，综合冷却效果先减小后增大，变化幅度为6.56%，冲击靶面Nu先减小后增大，单位面积冷却气量减小，减小幅度达15.82%；随周向曲率半径的增大，气膜冷却表面的综合冷却效果先减小后增大，变化幅度为1.04%，冲击靶面Nu减小，单位面积冷却气量减小，减小幅度为3.48%；相比于周向曲率半径对双层壁隔热屏冷却性能的影响程度，正流向曲率半径的影响程度为3倍左右，负流向曲率半径的影响程度为6倍左右。相比于周向曲率半径，流向曲率半径的变化对双层壁隔热屏冷却性能的影响更强烈。

Abstract:

In order to obtain the effects of flow and circumferential curvature radio on the cooling performance of double-wall heat shield，this paper is based on the operating conditions of a double-wall heat shield curved surface of circular-to-rectangular transition section of the tail of some-type afterburner. The results were obtained by studying five models with different circumferential bending curvature radius and six models with different flow bending curvature radius. Three-dimensional flow-thermal coupling numerical simulation method was applied to study the effects of flow and circumferential curvature radio on the cooling performance of double-wall heat shields. The trend of overall cooling effects of film cooling surface，Nusselt number Nu of impinged surface and the cooling air flow per unit area were obtained. The results show that with the increase of positive flow curvature radius，the overall cooling effect increases first and then decreases and the variation is up to 3.18%，Nu decreases first and then increases，the cooling air flow per unit area increases and the variation is up to 9.78%. With the increase of negative flow curvature radius，the overall cooling effect and Nu both decrease first and then increase，the variation of overall cooling effect is up to 6.56%，Nu decreases first and then increases，the cooling air flow per unit area decreases and the variation is up to 15.82%. With the increase of circumferential curvature radius，the overall cooling effect decreases first and then increases and the variation is up to 1.04%，Nu decreases，the cooling air flow per unit area decreases and the variation is up to 3.48%. Compared with the influence of the circumferential curvature radius on the cooling performance of the double-wall heat shield，the influence of the positive flow curvature radius is about 3 times，and the negative flow curvature radius is about 6 times of that. The variation of flow curvature radius has a stronger influence on the cooling performance of the double wall heat shield compared to the variation of circumferential curvature radius.