Critical heat flux (CHF) of liquid hydrogen (LH2) flow boiling under microgravity is vital for designing space cryogenic propellant conveying pipe since the excursion of wall temperature may cause system failure. In this study, a two-dimensional axisymmetric model based on the wall heat flux partition (WHFP) model was proposed to predict the CHF condition under microgravity including the wall temperature and the CHF location. The proposed numerical model was validated to demonstrate a good agreement between the simulated and experimentally reported results. Then, the wall temperature distribution and the CHF location under different gravity conditions were compared. In addition, the WHFP and vapor-liquid distribution along the wall under microgravity were predicted and its difference with terrestrial gravity condition was also analysed and reported. Finally, the effects of flow velocity and inlet sub-cooling on the wall temperature distributions were analysed under microgravity and terrestrial gravity conditions, respectively. The results indicate that the CHF location moves upstream about 5.25 m from 1g to 10⁻⁴g since the void fraction near the wall reaches the breakpoint of CHF condition much earlier under the microgravity condition. Furthermore, the increase of the velocity and decrease of the sub-cooling have smaller effects on the CHF location during LH2 flow boiling under microgravity.

在微重力下沸腾的液态氢（LH2）流动的临界热通量（CHF）对于设计空间低温推进剂输送管至关重要，因为壁温的偏移可能会导致系统故障。在这项研究中，提出了一种基于壁热通量分配（WHFP）模型的二维轴对称模型，以预测微重力作用下的CHF条件，包括壁温和CHF位置。所提出的数值模型经过验证，可以证明模拟结果和实验报告结果之间的良好一致性。然后，比较了不同重力条件下的壁温分布和CHF位置。此外，预测了微重力作用下WHFP和沿壁的气液分布，并分析了其与地面重力条件的差异。最后，分别在微重力和地面重力条件下分析了流速和入口过冷度对壁温分布的影响。结果表明，CHF位置从1开始向上游移动约5.25 m。克至10 ^-4克由于壁附近的空隙率达到CHF条件断点的微重力条件下要早得多。此外，在微重力作用下，LH2流沸腾期间，速度的增加和过冷的减少对CHF位置的影响较小。