灭火弹气体发生器内流场数值模拟

为了提高灭火弹灭火性能，优化灭火弹结构设计，利用Fluent对灭火弹气体发生器内流场进行仿真计算，通过改变气体发生器开孔情况及发生剂参数调整弹内流场分布。计算结果显示:当首孔距离等于15倍气体发生器排气孔孔径时，灭火弹壳体近壁面存在5个大小相近且数值较高的压强峰，压力分布最利于灭火弹壳体预制孔槽破裂；灭火弹内气体发生器上排气孔对称性越强，发生器内压力分布越均匀。经过试验验证，仿真所得压力-时间曲线与试验测得数据吻合良好，说明该模型适用于灭火弹内流场仿真。 

Numerical simulation of internal flow field in gas generator of fire extinguishing bomb

In order to improve the fire-fighting performance and optimize the structure design of fire extinguishing bombs，Fluent was used to simulate the flow field in the gas generator of fire extinguishing bombs，and the flow field distribution in the bomb was adjusted by changing the opening of the gas generator and the parameters of the propellant.The calculation results showed that when the first hole distance was equal to 15 times the gas generator exhaust hole diameter，there were 5 pressure peaks of similar size and higher value on the near wall surface of the fire extinguishing bomb shell，and the pressure distribution was most conducive to the rupture of the prefabricated hole slot of the fire extinguishing bomb shell；the stronger symmetry of the exhaust holes on the gas generator in the fire extinguishing bomb indicated more uniform pressure distribution in the generator.The experimental verification showed that the pressure-time curve obtained by the simulation was in good agreement with the measured data，indicating that the model is suitable for simulation of the internal flow field of the fire extinguishing bomb.