Simulations on effects of rated ullage pressure on the evaporation rate of liquid hydrogen tank. (May 2019)

• Record Type: Journal Article
• Authors: Zhou, Rui; Zhu, WenLi; Hu, Zhenggen; Wang, Shunhao; Xie, Huangjun; Zhang, Xiaobin
• Is Part Of: International journal of heat and mass transfer. Volume 134(2019)
• Page Start: 842
• Page End: 851
• Publication Date: 2019-05
• Subjects: Liquid hydrogen -- Tank -- Self-evaporation -- CFD; Heat -- Transmission -- Periodicals; Mass transfer -- Periodicals; Chaleur -- Transmission -- Périodiques; Transfert de masse -- Périodiques; Electronic journals; 621.4022
• DOI: 10.1016/j.ijheatmasstransfer.2019.01.091
• Languages: English
• ISSNs: 0017-9310

Abstract

Highlights: Vaporization in LH2 tank with supports on two ends are modeled. Thermal boundary is theoretically determined in consideration of ice formation. Effects of rated ullage pressure on LH2 vaporization rate are illustrated. It is found that evaporation process includes three thermodynamic periods. Abstract: 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.