The self-pressurization process of a liquid hydrogen (LH2) tank in normal gravity due to the heat leakage through the insulation layer and the exposed supports is investigated using the computational fluid dynamic (CFD) approach. The ringlike supports are welded to the upper and lower ends of the cylindrical tank body. The Lee model is used to calculate the interfacial mass transfer, in which the accommodation coefficient is modified by trial test method and compared with the measured liquid level drop rate. In consideration of the possibility of ice formation on the foam and support surfaces exposed to the environment, the thermal boundary conditions are theoretically determined. A numerical strategy for controlling the ullage pressure is also presented to simulate the safety valve. Emphases are put on analyzing the effects of the rated ullage pressure on the evaporation rate. The results show that the whole evaporation process experiences three periods, which are pressure rise, liquid level invariant, and steady evaporation. The rated pressure has almost no effect on the duration of the pressure rise and the steady evaporation period. However, the duration of the liquid level invariant period is linearly related to the rated pressure. All of the mechanisms are explained in detail. Effects of the rated pressure on the temperature and flow distribution are also investigated. The calculation can be used to optimize the cryogenic tank operation for long-time storage. (C) 2019 Elsevier Ltd. All rights reserved.