均匀自由场中球形TNT装药爆炸数值计算分析

为更加精确地描述宽范围内均匀自由场中球形装药爆炸过程的特性,采用球形非等温爆炸模型,考虑装药爆炸近区高温高压条件下真实空气的特殊性质,引入真实空气量纲一拟合状态方程和JWL爆轰产物状态方程,建立拉格朗日球形坐标系下完备的量纲一流体动力学方程组;采用对点源强爆炸自模拟数值解的结果进行样条插值作为初始条件,将人工黏性法与激波装配法相结合,采用显式中心差分格式进行数值求解。通过算例计算,得到冲击波不同时刻的波形曲线和主激波峰值超压衰减曲线,通过拟合得到宽范围内的主激波峰值超压计算公式,计算值与有关文献以及实验较为吻合,验证了公式的准确性。结果表明,采用真实空气状态方程得到的结果适用于描述装药空中爆炸近区和远区流场特性。

Numerical calculation of characteristics of TNT spherical charge blast in uniform free field

A spherical non-isothermal blasting model was used to describe the characteristics of spherical charge blasting in uniform free field in wide range more accurately. Considering the special characteristics of real air in the near field of charge blasting under high temperature and high pressure, the fitted dimensionless equation of state of real air and the JWL(Jones-Wilkins-Lee) equation were used to construct the complete dimensionless hydrodynamic equations in Lagrangian spherical coordinate system. The interpolation calculation of the results of numerical solutions of intense explosions was used as the initial conditions. Combined the artificial viscosity technique with the fitting technique, the explicit scheme was used to solve the particle difference equations. By calculating, the wave profiles at different time and the attenuation curve of peak overpressure for TNT charge blasting in air were presented. A fitting equation for calculating the peak overpressure of mail shock wave within a wide distance range of charge blasting was obtained, and the results were compared with other available data to verify the validity of the presented equation. The applicability of the presented method in describing the near and far fields of charge blasting in air is demonstrated.