基于SPH-FEM算法的森林灭火弹爆炸抛撒灭火剂初速的数模拟研究

Numerical simulation of initial velocity of fire extinguishing agent in forest fire bomb explosion based on SPH-FEM algorithm

针对森林灭火弹爆炸抛撒问题,应用LS-DYNA软件对森林灭火弹爆炸抛撒灭火剂初速进行数值模拟研究。依据森林灭火弹爆炸抛撒实验的数据,对Gurney公式进行修正;建立森林灭火弹的仿真模型,将仿真模型所得灭火剂初速与修正后Gurney公式所得灭火剂初速进行对比,验证SPH-FEM耦合算法研究此类问题的可行性;对森林灭火弹装药结构进行优化,分析阶梯装药结构对灭火剂初速的影响。结果表明,修正后Gurney公式能够更好地适用于灭火剂初速的计算;采用SPH-FEM耦合算法模拟所得灭火剂初速与修正后Gurney公式所得灭火剂初速的吻合度高,表明采用SPH-FEM耦合算法研究此类问题是可行的;对森林灭火弹装药结构进行阶梯化改进可以增大灭火剂抛撒面积与提升灭火剂抛撒均匀性,提高森林灭火弹灭火效率。

In order to solve the problem of explosion and dispersion of forest fire extinguishing bombs,the initial velocity of explosion and discharging of fire extinguishing agent was studied by LS-DYNA software.According to the data of the explosion and scattering experiment of forest fire extinguishing bombs,the Gurney formula was modified.A simulation model of forest fire extinguishing bombs was established,and the initial velocity of the fire extinguishing agent obtained by the simulation model was compared with the initial velocity of the fire extinguishing agent obtained by the modified Gurney formula,so as to verify the feasibility of the SPH-FEM coupling algorithm to study such problems.The structure of the charge of the forest fire extinguishing bomb was optimized,and the influence of the stepped charge structure on the initial velocity of the fire extinguishing agent was analyzed.The results show that the modified Gurney formula can be better applied to the calculation of the initial velocity of the fire extinguishing agent.The initial velocity of the extinguishing agent simulated by the SPH-FEM coupling algorithm is in good agreement with the initial velocity of the extinguishing agent obtained by the modified Gurney formula,which indicates that it is feasible to study such problems by using the SPH-FEM coupling algorithm.The stepwise improvement of the charge structure of forest fire extinguishing bombs can increase the area of fire extinguishing agent and improve the uniformity of fire extinguishing agent dispersion,and improve the efficiency of forest fire extinguishing bombs.