带有钝体的弹用固体燃料冲压发动机工作性能

为发展一种弹用高性能冲压发动机，提出了在补燃室带有钝体的发动机设计方案，并数值计算对比分析了补燃室有无钝体方案下的内流场、燃烧效率、推力、比冲与总压损失。结果表明：钝体后部孔隙外侧有两个漩涡，孔隙内的高速气流与下部漩涡在一定程度维持了尾迹的稳定性，能够保证冲压发动机工作的平稳性；与参考固体燃料冲压发动机（不带钝体结构方案）相比，在补燃室中增加钝体能提高补燃室下游燃料与空气的掺混效果与温度，当进气质量流率为0.3 kg/s时，可使发动机推力和比冲提高约16.21%、燃烧效率提高约20.50%，但此增益效果会随着空燃比的增大而减小；当燃烧效率相同时，在补燃室中增设钝体，可以有效地缩减冲压发动机长度，为其他部件提供安装空间。

Performance of Solid Fuel Ramjet with Central Bluff Body for Projectile

To develop a high-performance ramjet for projectiles, a scheme of using bluff bodies in the combustion chamber of the solid fuel ramjet is proposed. The turbulent combustion model is established based on equations for Reynolds transition and eddy dissipation, and the internal flow field, combustion efficiency, thrust, specific impulse and total pressure loss of the combustion chamber with or without the bluff body are compared and analyzed by numerical calculation. The findings show that there are two vortices outside the pore behind the central bluff body. The high-speed airflow in the pore and small-scale vortices below has maintained some wake stability, which can ensure the smooth operation of the ramjet. Compared with the reference solid fuel ramjet (without bluff body structure), adding a bluff body in the afterburning chamber can improve the mixing effect and temperature of fuel and air at the downstream of this chamber, which can increase the combustion efficiency. When the intake air mass flow rate was 0.3 kg/s, the ramjet thrust and specific impulse was increased by about 16.21%, and the combustion efficiency improved by about 20.50%, but the enhancement effects would decrease with the increase of air-fuel ratio. Under the same combustion efficiency, adding a bluff body in the combustion chamber can effectively reduce the length of the ramjet and thus leaving installation space for other parts.