化工厂火灾-泄漏耦合作用下氯气扩散的数值模拟

Numerical Simulation of Chlorine Gas Diffusion under Fire-leakage Coupling in Chemical Plants

为研究化工厂火灾和有毒气体耦合作用下的气体扩散规律,采用FDS软件分别对某化工厂氯气泄漏、火灾和火灾-泄漏耦合条件下的氯气泄漏扩散进行了数值模拟,研究了火源功率、氯气泄漏时间等参数对环境温度和氯气浓度分布的影响规律。结果表明:化工厂氯气泄漏条件下,氯气主要在风的作用下沿着地面快速向下风向扩散;火灾条件下,厂房内的温度主要是以火源为中心随着距离的增加逐渐降低;而火灾-泄漏耦合条件下,氯气的泄漏扩散和火灾温度场都会发生显著的变化,一方面火灾产生的高温和热气流会使一部分原本沿着地面扩散的氯气在火源上风向附近向上扩散,同时下风口的火灾对氯气的扩散具有一定的阻隔作用,会减缓氯气向出口处扩散,另一方面泄漏出来的氯气会吸收空气中一部分热量从而降低泄漏口附近的温度。该研究结果可为化工厂危险区域的划分及事故救援提供参考。

The paper makes a numerical simulation of the diffusion of chlorine gas leakage in a chemical plant under chlorine gas leakage,fire and fire-leakage coupling conditions by Fire dynamic simulator(FDS) to investigate gas diffusion properties.The paper investigates effects of parameters,including fire power and leakage rate,on the distribution of temperature and chlorine concentration.The results show that under the leak condition,the chlorine gas diffuses downwind rapidly along the ground mainly under the action of the wind.Under fire conditions,the temperature in the workshop is mainly reduced with the increase of the distance centering on the fire source.Under the fire-leakage coupling,the leakage of chlorine gas and the temperature field of the fire will change significantly.On one hand,the high temperature and hot air flow caused by the fire will lead a part of chlorine gas around the fire source to spread upward near the fire source.And the fire show certain blocking effect on the diffusion of chlorine gas.It will slow the spread of chlorine to the outlet.On the other hand,the leaked chlorine gas absorbs a part of the heat in the air to lower the temperature near the leak.The simulation results can provide some reference for the division of dangerous areas and the rescue.