自动机喷管激波的时空衍变仿真与验证

自动机喷管不同的结构形式对后坐冲击的对冲效率是不同的,为了获得更好的喷管激波消减后坐冲击的方案,构建了不同结构的喷管模型；利用燃气可压缩雷诺平均N-S方程,对不同结构的激波时空衍变的过程进行仿真,得出流场图谱、火药气体载荷分布,通过分析激波温度、压力、马赫数的变化趋势,方案1和方案2的载荷峰值具有较大差异,初始阶段形成高度欠膨胀,射流核心区半径很大,之后膨胀强度衰减,核心区域变小,从激波马赫数云图可见,最大马赫数分别约为10和7,方案2初始阶段气流冲击在排气装置中央的芯锥上,形成一个沿着x轴的83KN脉冲载荷,这与试验中后坐力测试数据基本吻合。由于排气装置外部形状差异,球面波绕过装置产生的载荷波动有些细微不同。通过仿真与试验对比,方案1的反后坐能力比方案2更优,具有更为高效的后坐力对冲机制。

Simulation and verification of shock wave evolutionin nozzle of automatic gun

Different structure forms of automatic nozzle have different hedge efficiency to recoil impact. In order to obtain a better scheme to reduce recoil shock, nozzle models with different structures are constructed. The spatiotemporal evolution process of shock wave with different structures is simulated by using compressible Reynolds average N-S equation of gas, and the flow field diagram and propellant gas load distribution are obtained After analyzing the change trend of shock wave temperature, pressure and Mach number, the peak load of scheme 1 and scheme 2 are quite different. In the initial stage, the high underexpansion is formed, the radius of jet core area is large, and then the expansion strength decreases, and the core area becomes smaller. From the shock wave Mach number cloud chart, the maximum Mach number is about 10 and 7 respectively, and the air flow impinges on the center of the exhaust device in the initial stage of scheme 2 A 83kn pulse load along the x-axis is formed on the cone, which is basically consistent with the recoil test data. Due to the different shape of the exhaust device, the load fluctuation caused by the spherical wave bypassing the device is slightly different. Through the comparison of simulation and experiment, the recoil ability of scheme 1 is better than that of scheme 2, and has a more efficient recoil hedging mechanism.