A three-dimensional CFD model for large-scale liquid hydrogen spills is developed and validated by the experiments carried out by NASA. The effect of humidity on the development of hydrogen vapor cloud is emphasized, with the modified expressions of Lee model accounting for the phase changes of water and hydrogen. The results show that the numerical prediction is more consistent with the experiment considering the presence of air humidity. The condensation of water in the atmosphere increases the buoyancy of the vapor cloud, and promotes the diffusion of the cloud in vertical direction. The dimension of the cloud in streamwise direction changes little under different humidity, due to the balance between the height-dependent wind speed and the induced buoyancy. The scope of visible cloud indicated by the condensed water vapor expands with the increasing air humidity, and still lies within the flammable domain when the relative humidity approaching to 75%. Water vapor condensation induces the cloud temperature rise under the same concentration, and the leeward part is more influenced compared with the upwind part.

通过美国国家航空航天局（NASA）进行的实验，开发并验证了大规模液态氢泄漏的三维CFD模型。强调了湿度对氢蒸气云发展的影响，Lee模型的修正表达式考虑了水和氢的相变。结果表明，考虑到空气湿度的存在，数值预测与实验更加吻合。大气中水的凝结增加了蒸气云的浮力，并促进了蒸气云在垂直方向上的扩散。由于高度相关的风速和感应浮力之间的平衡，在不同湿度下，沿流向的云尺寸几乎没有变化。冷凝水蒸气指示的可见云的范围随着空气湿度的增加而扩展，并且当相对湿度接近75％时仍位于易燃区域内。在相同浓度下，水蒸气凝结引起云温升高，并且与上风部分相比，下风部分受到的影响更大。