Experiment and simulation of LNG self-pressurization considering temperature distribution under varying liquid level

For LNG-fueled ships, estimating the rate of self-pressurization is critical because the pressure limit of an LNG storage tank and the specifications of the boil-off gas processing system depend on the pressure rise rate. However, estimation using a non-equilibrium model exhibits deviated prediction on the pressure increase when thermal stratification is occurred in LNG. Therefore, in this study, a new numerical model is proposed for estimating the self-pressurization of LNG by considering the nonuniform one-dimensional fluid temperature distribution at varying LNG levels. The suggested model was verified using a pilot-scale experiment with a 150 m3 LNG tank capacity. The results show that the proposed model can explain the limited evaporation at a higher level and the vigorous evaporation at a lower level. Furthermore, the suggested model exhibits that the temperature profile in LNG can…