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

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.