高速冲压推进动能弹自点火工作过程数值模拟研究

Study on N um erical Sim ulation of the Self-ignition Operating Process of High-speed Ram jet Kinetic Energy Projectile

为了研究高速冲压推进动能弹在自点火过程中的工作特性,数值模拟了基于聚乙烯为固体燃料的高速冲压推进动能弹自点火过程,分析了自点火过程中的点火延迟时间,喷管出口堵盖打开前燃烧室的流场变化规律,以及堵盖打开火焰稳定后燃烧室流场变化规律和全弹性能。结果表明:高速冲压推进动能弹由于其初始的独特结构(喷管出口堵塞),点火延迟时间短,自点火能够成功进行;堵盖打开前,燃烧室压力发生了剧烈的振荡,并且燃烧室内化学反应增强了振荡效应;堵盖打开并且燃烧室火焰稳定后,高速冲压推进动能弹的额定推力为283 N,净推力为83 N,基于聚乙烯燃料的比冲为9129 m·s-1。

To research the operating characteristics of high-speed ramjet kinetic energy projectile during the process of self-ignition, the process of self-ignition of high-speed ramjet kinetic energy projectile based on the solid fuel of polyethylene was numerically simulated. The ignition delay time in the self-ignition, the change law of flow field in combustor before the blanking cap opening, and the change law of flow field and performance of the entire ramjet after the flame in combustor stabilizing when the blanking cap opening were analyzed. Results show that because of its initial unique structure whose exit of nozzle is blocking, the ignition delay time is short enough, so the self-ignition can be successfully performed. Violent oscillation of pressure is occurred in the combustion chamber before the blanking cap opening, and chemical reaction in the combustion chamber enhances the effects of oscillation. After the blanking cap opening and flame in combustor stabilizing, the high-speed ramjet kinetic energy projectile＇s rated thrust is 283 N and its net thrust is 83 N. The specific impulse based on polyethylene is 9129 m · s-1.