膨胀波火炮扩张喷管减后坐数值模拟

Numerical Simulation of Recoil Reduction for Expansion Nozzle in RAVEN

为了研究膨胀波火炮扩张喷管在发射过程中所受作用力的大小,利用二维非定常Euler方程并结合Roe一阶迎风格式,采用动态铺层的结构化网格方法模拟发射过程中惯性炮闩与身管的相对运动。用proflie文件将内弹道求得的惯性炮闩运动状态赋予闩体,利用UDF对膛内时期流场的压力、速度、温度进行初始化,从闩体打开的瞬间开始进行仿真,监测发射过程中闩体和扩张喷管的受力,进而求得膨胀波火炮的炮膛合力与其冲量,并与同等发射条件下闭膛火炮炮膛合力冲量进行比较,较以往的经验公式计算更为准确,为计算膨胀波火炮减后坐性能提供了新方法。结果表明,与传统闭膛火炮相比,在初速基本保持不变的情况下,膨胀波火炮发射过程中炮膛合力冲量减少达48.4%.

In order to study the force acting on the expansion nozzle of RAVEN in the launching process, the two-dimensional unsteady Euler equation and the first-order upwind format of Roe were used to simulate the relative motion of the inertial breechblock and barrel with the dynamic layered structural grid method. Given the breechblock motion state obtained from the interior ballistics from the profile file, the pressure, velocity, and temperature of the flow field in the bore are to be initialized through the use of UDF. The simulation is carried out from the moment when the breechblock body is opened. The force of the breechblock body and RAVEN is monitored in the process. Then the bore force and impulse of the expanding wave gun are obtained, with the bore force of RAVEN with that of the closed bore gun under the same firing conditions. Compared with the previous empirical formula, the calculation of force impulse is more accurate, which provides a new method for calculating the recoil reduction performance of RAVEN. The result shows that, compared with the traditional closed chamber gun, when the initial velocity of the gun is basically unchanged, the bore resultant combined force momentum in RAVEN is reduced by 48.4%.