Numerical simulation and experiment verification of the static boil-off rate and temperature field for a new independent type B liquefied natural gas ship mock up tank

Abstract

In this paper, a new independent type B liquefied natural gas (LNG) ship mock up tank with the net capacity of 40 m3 and an insulation thickness of 400 mm was taken as the research target. After reasonable simplification, two-phase flow and phase change heat transfer of cryogenic fluid in the mock up tank was simulated by using unsteady three-dimensional CFD method. Volume of fluid (VOF) model was selected to track the vapour-liquid interface, Lee model was used as the phase change model, and the influence of the static pressure on the phase change model was considered. The temperature distribution and the static boil-off gas (BOG) generation rate of the mock up tank was calculated, and working conditions of the simulated tank under different liquid levels and partial insulation system damage were discussed. The pressurization characteristics of the mock up tank under closed conditions was also studied. Comparing the simulation with the experimental results, it showed that this model could effectively simulate the evaporation process of cryogenic liquids in the mock up tank under stationary conditions, which provides an important reference for the design and improvement of the new independent type B LNG ship.