Multiphase-thermal simulation on BOG/BOR estimation due to phase change in cryogenic liquid storage tanks
Multiphase-thermal simulation on BOG/BOR estimation due to phase change in cryogenic liquid storage tanks
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DOI：
10.1016/j.applthermaleng.2020.116264
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发表时间：
2021-01-13
影响因子：
6.4
通讯作者：
Choi, Seongim
中科院分区：
文献类型：
--
作者：
Jeon, Gyu-Mok;Park, Jong-Chun;Choi, Seongim
本研究的目的是利用高保真多物理CFD数值模拟绝热系统的传热和低温液舱内多相热流的相变，对安全壳货物系统设计中低温液体的沸腾气体(BOG)和沸腾速率(BOR)进行高精度的数值计算。计算结果与传统低保真方法的预测结果进行了比较。传统的低保真方法仅基于总传热，没有考虑与储罐内低温液体相变相关的详细物理因素。用商业软件STAR-CCM+求解了采用Realizable k-epsilon湍流模型和Rohsenow沸腾模型的非定常雷诺平均Navier-Stokes(URaNS)方程。首先，为了验证相变模型，对储存在C型独立储罐中的低温液体进行了计算，研究了储罐内的热流体行为，并将相应的BOG和BOR值与实验值以及其他研究人员的数值模拟结果进行了比较。BOR值的估计值与误差小于1%有很好的一致性，精确地解决了低温液体蒸发引起的热对流问题。随后，对膜式液化天然气(LNG)储罐内的多相热流进行了BOR计算，并考虑了隔热系统的导热作用。模拟结果表明，采用相变模型的高保真CFD计算能够准确地预测低温液体的汽化过程，并能根据实际的BOG量计算出正确的BOR值。
The purpose of the study is the high-precision, numerical calculation of the Boil-off-Gas (BOG) and Boil-off-Rate (BOR) of cryogenic liquid for the design of containment cargo system (CCS) by using high-fidelity multi-physics CFD simulation of heat transfer of insulation system and phase change of multiphase-thermal flow in the cryogenic liquid tank. The results are compared with those predicted by the conventional low-fidelity methods which are based only on the total heat transfer and does not consider detailed physics related to the phase change of the cryogenic liquid in the storage tank. The unsteady Reynolds-averaged Navier-Stokes (URaNS) equations with the realizable k-epsilon turbulence model and the Rohsenow boiling model for phase change calculation are solved by commercial software of STAR-CCM+. First, for the validation of the phase change model, the cryogenic liquid stored in an independent tank of type C is calculated to study thermal fluid behaviors inside the tank and the corresponding values of BOG and BOR are compared with the experiments as well as the results from numerical simulations by other researchers. The estimated BOR value showed an excellent agreement with discrepancy less than 1%, resolving precisely the thermal convection caused by the vaporization of the cryogenic liquid. Subsequently, the multiphase-thermal flow in a membrane-type LNG (liquefied natural gas) storage tank was calculated for the BOR estimation, coupled with thermal conduction through the insulation system. It is concluded from those simulations that the high-fidelity CFD calculation with the phase change model was able to precisely predict the vaporization of the cryogenic liquid and to calculate the correct BOR values based on the actual BOG amount.