低温射流抑制空间液氢储罐温度分层的数值研究

液氢是一种常用的沸点低、易蒸发的空间低温推进剂.空间微重力环境中浮力对流被极大减弱甚至完全抑制，当推进剂储罐壁面存在局部漏热时，储罐内部气液两相流会出现环绕漏热源的温度分层现象，引起局部过热沸腾，导致储罐内部压力急剧增大，危害系统结构安全.利用低温射流抑制温度分层现象是一种有效手段.低温流体通过设置在储罐内部的射流喷嘴与储罐内部的流体混合，消减局部高温，实现温度的均匀化.本文采用全充满的二维缩比储罐模型，对微重力条件下液氢储罐内局部漏热引起的温度分层现象进行数值模拟，分析低温射流条件对于消除微重力条件下液氢储罐内部温度分层效果的影响. 

Destratification in Hydrogen Propellant Tank in Space by Jet Injection

Hydrogen plays a vital role in the future energy system as a space propellant, but it is sensitive to heat leakage from the environment because of low boiling point and low density. On the other hand, the buoyancy convection in the space microgravity environment is weakened and even completely suppressed. When there is local heat leakage on the wall of the propellant tank, temperature stratification will happen around the heat leakage source, causing local overheating. This affects the interfacial heat and mass transfer, causing the tank pressure to rise, and jeopardize the structural safety of the system. To prevent the tank pressure from rising above the design of limits, venting or active pressure control techniques must be implemented. The cryogenic jet mixing is an effective means to suppress temperature stratification. The cryogenic fluid is mixed with the fluid inside the tank through a jet nozzle to reduce the local high temperature and achieve uniform temperature. In this paper, the temperature stratification phenomenon caused by local heat leakage under microgravity condition is numerically simulated by using a fully filled two-dimensional scale tank model, and then the influence of different cryogenic jet mixing conditions on eliminating the temperature stratification effect is analyzed.