制冷机和导热带耦合作用的低温容器内BOG蒸发过程模拟分析

Simulation and analysis of BOG evaporation process in cryogenic vessel with coupling effect of refrigerator and thermal strap

采用Ansys Workbench软件,对制冷机和导热带耦合作用的低温容器内BOG蒸发过程进行模拟,研究容器内流体温度场和速度场变化规律。结果表明:容器内液氮形成从侧壁到中心,温度不断降低的热分层;靠近容器壁处液氮温度场和速度场按照从上到下的顺序,从气液界面开始依次发生变化;当底部液氮发生明显的温度分层后,开始由容器底部向气液界面发展,最后液氮主体温度趋于均匀;导热带传递的热量对容器内流体温度场和速度场分布有影响,不同时刻由于气液界面附近导热带温度的不同,导致该处流体温度场形状有差异;容器底部热流体上升过程中在导热带下端的容器底部处形成涡旋,涡旋破碎后的热流体沿导热带两侧向气液界面运动。

In order to study the variation rules of temperature and velocity fields of the fluid in the vessel,evaporation process of BOG in cryogenic vessel with coupling effect of refrigerating machine and thermal strap was simulated by Ansys Workbench software.The results show that the liquid nitrogen in the container forms a thermal stratification from the sidewalls to the center with decreasing temperature,the temperature and velocity fields of liquid nitrogen near the vessel wall change successively from top to bottom,starting from the gas-liquid interface,and the liquid nitrogen starts to develop from the bottom of the vessel to the gas-liquid interface when it has obvious temperature stratification at the bottom until the temperature of the liquid nitrogen tends to be uniform.The heat transfer of thermal strap has an influence on the temperature and velocity field distribution of the fluid in the vessel.Due to the temperature difference in the thermal conduction zone near gas-liquid interface at different times,the shape of the fluid temperature field is different.A vortex is formed in bottom of the container under thermal strap,and the thermal fluid moves along both sides of the thermal strap zone towards the gas-liquid interface after the vortex is broken.