火烧环境下包装箱结构的热响应有限元模拟

THERMAL RESPONSE SIMULATIONS OF THE PACKING CONTAINER IN FIRE ENVIRONMENT USING THE FINITE ELEMENT METHOD

炸药的包装箱为典型的金属-木材-金属结构,包装箱内的云杉木材主要起到阻热和吸热的作用.论文基于有限元法对池火条件下的包装箱进行热分析,建立包装箱热模型时考虑了对流和辐射两种边界条件,采用焓值变化考虑木材的水分汽化吸热和热解吸热过程.计算结果表明包装箱内部的温度分布受到木材水分汽化、热解和木材厚度的显著影响.在包装箱火烧相同时刻,两种不同厚度的木材具有类似的碳化层厚度.计算结果还表明木材在碳化层界面处有大的温度梯度,这说明云杉是良好的隔热材料.

The packing container of the high explosive is a representative metal-wood-metal structure.The spruce wood filled in the packing container can effectively resist heat transfer and absorb heat.The thermal analysis of the packing container in the pool fire environment is presented with the finite element method.The thermal model of the packing container is established with the convection and radiation boundary conditions.In these simulations,the heat consumed by the water evaporation of wood and the pyrolysis of wood is calculated using the enthalpy change.The computed results show the inner temperature distributions of the packing container are significantly affected by some factors,such as the water evaporation of wood,the pyrolysis of wood and the thickness of wood.For the same time,the simulations show the char layer thickness is similar in two thickness wood columns.The computed results also show there are large temperature gradients in the interface of char and wood.This demonstrates the spruce wood is the excellent thermal resistance material.