Mixing and heat release characteristics in the combustor of solid-fuel rocket scramjet based on DES

Abstract

Based on the previous experimental results, in order to improve the understanding of the mixing and heat release process of the internal flow field in the solid-fuel scramjet combustor, and to provide theoretical reference for the layout of the combustor configuration in the next step, the numerical simulation method of DES combined with the gas mixing degree, mixing layer thickness and mixing fraction was used to analyze quantitatively the microscopic structures and the mixing combustion enhancement mechanism in the combustor at different lobe sweep angles based on the influence of the change of lobe sweep angle on engine performance, and then the influence law was explained from the microscopic point of view. Results demonstrate that 1) based on the engine configuration in this paper, in the design process of staggered support plate structure, the lobe sweep angle should be based on the width and the straight section length of the support plate. And the engine performance improves with the decrease of the lobe sweep angle. 2) The growth of the reaction mixture layer is in four typical stages: the initial growth zone, the rapid growth zone, the saturated growth zone and the full development zone. 3) The downstream part of combustor is in the full development zone of the reaction mixing layer. The full development zone as the main area determining the heat release performance of the engine, the mixing degree increases with the decrease of the lobe sweep angle in the behind part of the combustor. Therefore, the pressure in the downstream flow passage of the combustor and the space of combustor occupied by the high pressure area increase with the decrease of the lobe sweep angle.