Effects of environmental temperature and wind velocity on underwater LNG vessel leakage

Abstract

The heat and mass transfer between liquefied natural gas (LNG) and the environment caused by an LNG vessel leakage underwater was simulated using FLUENT software under different conditions of environment temperature and wind velocity. The VOF was used to define heat and mass source terms, and an experimental average heat exchange velocity value was applied to the environment of the leak. Through numerical simulations, the authors derived distributions of flow, temperature, viscosity, and ice forming mechanisms. A rule was derived for LNG and NG mass changes with time due to boiling. Mechanisms for heat and mass transfer in an LNG vessel's underwater leakage were discussed. On that basis a formula for the effect of environmental temperature and wind velocity on the simulation was proposed. The results show that in high temperature seas there will still be low temperature LNG, but because of violent motion caused by the LNG's rapid phase change, the formation of ice is difficult. When un-boiling LNG reaches the surface of the sea, phase change then forms ice. The higher the environmental temperature and wind velocity, the greater the quantity of heat and mass transferred, the lower the quantity of ice formed.