Large eddy simulation for the rapid phase transition of LNG

Abstract The environmental concerns on the use of fossil fuels have incentivized the utilization of cleaner solutions for energy supply. Natural gas in the form of a liquid (LNG) is considered a promising and highly attractive alternative due to the high density and relatively low cost of transportation. In the case of accidental release on water, elevated heat transfer causes rapid evaporation that has the potential to lead to a rapid phase transition (RPT), thus producing significant overpressures. In this work, the effects of composition, release rate, and the fluid dynamic regime of water on the RPT of LNG are analyzed by means of detailed analysis based on computational fluid dynamics and large eddy simulation for the turbulence model. The thermodynamic properties at ultra-low temperature related to the species considered in the mixtures are estimated by using an approach based on quantum mechanics. Results are compared with experimental analysis, quite satisfactorily. A preliminary conclusion shows that calm water, as within port facilities, decreases the likelihood of the RPT or its magnitude to a negligible intensity. On the contrary, the addition of ethane or propane may dramatically affect the explosive phenomenon.