氦气对低温液氧箱体分层压增的影响

Influence of Helium on Process of Thermal Stratification and Pressurization in Cryogenic Liquid Oxygen Tank

为研究气枕中氦气对低温液氧分层及压增的影响,以柱状液氧箱体为例,通过改变气枕中氦气以及氧气含量来改变箱体初始压力,分别计算了初始箱体压力相同以及初始箱体压力不同两种工况下液氧分层压增参数的变化。结果表明:氦气的存在增强了气枕与箱体壁面以及气液界面的对流换热,促进了界面的蒸发相变,并带来了质扩散传递。当箱体初始压力不变时,箱体压增以及气液界面相变量随着氦气含量的增加而增加。在初始氦含量由0.0kg增加到0.563kg的过程中,箱体压增增加了20.91%,气液界面总相变量增加到初值的7.87倍。当箱体初始氧含量保持不变时,箱体压增随着氦气含量的增加而减小,而界面总相变量则呈现相反的变化趋势。在初始氦含量由0.0kg增加到0.2kg的过程中,箱体压增下降了28.66%,但气液总相变量却增加到初值的4.3倍。

Cylindrical liquid oxygen tank is chosen to investigate the effect of helium on the process of thermal stratification development and pressurization.The initial tank pressure can be adjusted by changing proportions of gas helium and gas oxygen.The variations of thermal stratification and pressurization parameters are analyzed under conditions of equal and different initial tank pressure.It is found that gas helium enhances the natural convection intensity occurring between tank wall and liquid-vapor interface to strengthen evaporation phase change and mass diffusion.When the initial tank pressure keeps constant,both tank pressure increment and total phase change amount rise with increasing helium component.When the initial gas helium ranges from 0.0kg to 0.563 kg,the tank pressure increment rises by 20.91%,the total phase change amount rises by 7.87 times.When the initial oxygen keeps constant,the tank pressure increment drops with the increasing initial helium quantity,and the total phase change amount tends oppositely.When the initial gas helium ranges from 0.0kg to 0.2kg,the tank pressure increment drops by 28.66%,and the total phase change amount rises by 4.3times.