隧道内液化天然气管道泄漏火灾温度场的数值模拟

Numerical simulation of LNG leakage fire temperature distribution from pipeline in tunnel

以某实际液化天然气(LNG)输运工程为例,采用计算流体动力学方法,建立隧道内LNG管道泄漏火灾的数学模型,分别以3种不同的泄漏情况对LNG泄漏火灾流场进行了数值模拟计算,得到了3种不同泄漏强度的LNG火灾温度场的实时分布情况,并分别对其火灾温度场随时间的变化及危险性进行了分析。结果表明:泄漏强度最小的情况下,火灾发生后隧道温度升幅不大,温度变化幅度平缓,危险性相对较小;泄漏强度居中的情况下,火灾发生后隧道内温度变化幅度较大,变化趋势较为剧烈,危险性显著增加;泄漏强度最大的情况下,火灾发生后隧道内温度是3种情况中最高的,且隧道内会出现烟气堆积的情况,十分危险,应着力避免此类事故的发生。

Based on a real instance of liquefied natural gas （LNG） transportation engineering in a tunnel, a mathematical model of LNG leakage fire from pipeline was proposed with computational fluid dynamics （CFD） method. The LNG leakage fires under 3 different LNG leakage cases were simulated, and their changes in temperature distribution with time in the tunnel were calculated, through which the development of temperature distribution and fire risk were assessed. The simulation results showed that the rate in the tunnel temperature increase during fire is not high when the LNG leakage intensity is small, where the change in temperature is gentle and the fire risk is relatively low. The rate in tunnel temperature increase during fire is higher when the LNG leakage intensity is medium than the case of small intensity leakage, and the change in temperature is more severe, which makes the risk grow obviously. When the LNG leakage intensity is big, the fire temperature in the tunnel is highest among the three cases, the fire smoke will be seriously accumulated in the tunnel, which is very dangerous and should be avoided.