Study on Mass Burning Rate of LNG Pool Fire Using a Validated CFD Model

Liquefied natural gas (LNG) is widely used, because it provides an easy and economic solution to transport and store natural gas, especially when pipelines are not available. Pool fire is the major hazard of the LNG accident according to the report of the U.S. Government Accountability Office, because LNG fire has a large surface emissive power compared with other hydrocarbon fuels, which may lead to domino accident. Previous works have developed Computational Fluid Dynamics (CFD) models of LNG pool fire, but the mass burning rate was fixed manually as the model input, ignoring the fact that the mass burning rate is determined by the fuel’s physical properties and heat input to vaporize the fuel. In this work, a fire dynamics simulator (FDS) model of LNG pool fire controlled by material physical properties was developed and validated against a series of LNG pool fire experiments carried out by Mary Kay O’Connor Process Safety Center (MKOPSC). Statistical performance measurement shows that the model is superior to the semi-empirical formula in predicting the mass burning rate of LNG pool fire under different pool sizes. A flame geometry analysis software was developed by comparing the different algorithms, and the centroid method was selected. The results show that the fire model (200 kW/m³ as flame contour) can accurately predict the flame geometry in the experiment. The influence of wind speed and dike height on the mass burning rate was also studied by this model. The results show that the height of concrete dike is negatively correlated with the mass burning rate of LNG pool fire. The effect of wind speed on LNG mass burning rate is complicated. The forced convective boundary layer at lower wind speed will promote LNG combustion and increase the mass burning rate, while higher wind speed will reduce the mass burning rate by reducing thermal radiation feedback.

*Corresponding author: Bin Zhang, bzhang@njtech.edu.cn;