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

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.

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