Numerical investigation of LNG gas dispersion in a confined space: An engineering model

The present study has numerically investigated a dynamic methane leak and dispersion in a confined space. To establish a numerical prediction based engineering model of dynamic gas leak and dispersion in a confined space, numerical experiments are conducted for variation of a key parameter - leak hole size. Based on the numerical results data, an engineering model is developed. The parameters related to lower flammable limit of the methane were quantitatively analyzed to compare the potential risk due to a gas leak. To quantitatively investigate the flammable region, the longitudinal and transverse directional length is defined and studied. We found that the ratio between longitudinal and transverse directional length can be a bridge to model the flammable region. The aspect ratio of the flammable region is fitted by an exponential function to show the relation with time. Then, an oval-shape model is presented to predict flammable region. Oval-shape model is completed by the combination of aspect ratio relation and a function for transverse length. Finally, we compared the developed engineering model (oval-shape model) and numerical results. The engineering model can predict the flammable region quite well when it reaches steady state. It is expected that the established engineering model is valuable for the Quantitative risk assessment (QRA), initial emergency strategy preparation when a fuel gas leak accident happened in a Combined cycle power plant (CCPP). We hope it is also can be a kind of data base for power plant operation manual.