燃料抛撒成雾及其燃烧爆炸的光滑离散颗粒流体动力学方法数值模拟研究

燃料在炸药爆炸驱动下形成燃料空气爆炸云团, 进而引燃爆炸, 对目标造成毁伤. 本文在前期提出的光滑离散颗粒流体动力学方法(SDPH)的基础上, 引入描述炸药由爆轰到膨胀整个过程的Jones-Wilkins-Lee状态方程及描述气体快速燃烧过程的EBU-Arrhenius燃烧模型, 建立了求解战斗部起爆、燃料抛撒和燃料二次引燃爆炸问题的新型SDPH方法. 设计了圆环形燃料颗粒在炸药爆炸驱动下运动抛撒的算例进行数值验证, 结果与理论相符; 对燃料空气炸药(FAE)云雾的形成和发展过程进行了数值模拟, 分析了云雾的形态, 并与实验结果进行对比, 符合较好, 同时分析了不同起爆方式对云雾团成型的影响; 最后, 在云雾团成型的基础上, 引入蒸发燃烧模型对FAE的燃烧爆炸过程进行了模拟研究. 结果表明, 本文建立的数学模型和计算方法可以较好的模拟燃料空气炸药抛撒成雾及云雾燃烧爆炸过程, 为该类武器装备的设计研究提供了较好的数值方法.

Numerical simulation of fuel dispersal into cloud and its combustion and explosion with smoothed discrete particle hydrodynamics

A fuel air cloud is formed under the driving force of the explosive detonation and then it’s ignited to explosion to attack the target. The existing numerical simulations are mainly limited to the fuel dispersal processes which are all based on mesh methods. The fuel particles in the air cloud are difficult to traced. Otherwise, the computing process is complex and could not be solved by the exiting methods for the chemical reaction and the forming and propagation of shock waves are both involved in the fuel combustion and explosion. Smoothed discrete particle hydrodynamics (SDPH), as a new method to solve the gas-particle two-phase flow, has been successfully used to simulate the aeolian sand transport, heat transfer and evaporation. Based on the previous work, the Jones-Wilkins-Lee (JWL) function is imported to describe the explosive detonation to expansion and it is solved by finite volume method. The fuel drops dispersed by explosion are traced by the improved smoothed particle hydrodynamics. The drop evaporation model and the EBU-Arrhenius combustion model for gas high-speed combustion are introduced to describe the combustion and detonation of fuel drops. Then we build a new SDPH method to simulate the warhead initiation, fuel dispersal, and the fuel second explosion. Firstly, we design a test that is the dispersal of circular fuel drops drove by explosive detonation to validate our new method. The changing of the explosive detonation pressure and the velocity fields of explosive and particles are analyzed and they are consistent with the theory. And then, the forming and developing of FAE cloud are simulated. Through comparing with the experiments, the shapes of the cloud by the two methods coincide with each other. The effects of different initiations on the cloud forming are also analyzed. Finally, based on the cloud group forming, the evaporation and combustion models are introduced to study the combustion and explosion of FAE. We obtain the velocity field and the distribution of combustion product. The result indicates that the fuel dispersal into cloud and its explosion can be simulated better with the mathematical model and computational method built in this paper. This finding supplies a more effective numerical method for the design and research on this type of weapon equipments.