带有中心钝体的固体燃料冲压发动机工作性能分析

Performance Analysis of Solid Fuel Ramjet with Central Bluff Body

关键词:  固体燃料冲压发动机  涡旋燃烧  燃面退移速率  推力  燃烧效率

Key words:  Solid fuel ramjet  Vortex combustion  Burning surface regression rate  Thrust  Combustion efficiency

摘要:

为提高固体燃料冲压发动机的燃烧特性和工作性能，提出了带有中心钝体的固体燃料冲压发动机方案，基于雷诺转捩和涡概念耗散方程建立了其湍流燃烧模型，并数值计算分析了其内流场、燃面退移速率、推力与总压损失。结果表明：带有中心钝体的冲压发动机内部流动过程较为复杂，钝体后部有四个漩涡，增强了发动机内来流空气与燃气的掺混；钝体孔隙中的高速气流与两侧的小尺度漩涡保证了钝体尾涡的稳定性；与普通固体燃料冲压发动机相比，在燃烧室中增加中心钝体能增大燃烧室内高温区面积，提高补燃室内温度，可使推进剂平均燃面退移速率提高36.5%，发动机推力提高22.1%，燃烧效率提高8.9%。

Abstract:

In order to improve the combustion characteristics and working performance of the solid fuel ramjet， a solid fuel ramjet with a central bluff body is proposed. Based on the Renault transition and Eddy-Dissipation equations， the turbulent combustion model is established， and the internal flow field of the ramjet， as well as the regression rate， thrust and total pressure loss， were numerically analyzed. The results show that the internal flow process of the ramjet with a central bluff body is more complex. There are four vortices at the rear of the bluff body， which enhances the mixing of air and gas in the engine. The high-speed airflow in the blunt body pores and the small-scale vortices on both sides ensure the stability of the blunt body wake. Compared with the typical ramjet， adding a central bluff body in the combustion chamber could increase the area of high temperature zone in the SFRJ chamber and improve the temperature in the afterburner， which can increase the average burning surface regression rate of propellant by 26.1%， the thrust of engine by 22.1% and the combustion efficiency by 8.9%.