In this paper, the effects of the initial filling rate and heat flux density
on the natural convection inside the liquid hydrogen storage tank and the
variation laws of temperature and pressure are studied. The study found that
the optimal initial filling rate of the 250m3liquid hydrogen storage tank
was 86%.When the initial filling rate is in the range of 35% to 95%, the
change of the heat flux density has a greater impact on the
self-pressurization phenomenon than the change of the filling rate. When the
initial filling rate is lower than 35%, the pressure in the tank rises
sharply, and the change of the initial filling rate has a great influence on
the self-pressurization phenomenon. The high initial filling rate and high
heat flux density make the pressure rise of the liquid hydrogen storage tank
faster during the pressure recovery period. When the liquid hydrogen begins
to evaporate in large quantities, the low filling rate and high heat flux
make the tank pressure increase faster. By comparing the three thermodynamic
models with the simulation results, it is found that the pressure deviation
of the 250m3liquid hydrogen storage tank with a fillingrate of 86% is within
20% calculated by the three-zone model, which is the closest to the
simulation results. The deviation of the surface evaporation model at high
heat flux density and high filling rate reached 76% and 88.3%, respectively,
which was the most affected calculation model by the change of heat flux
density and initial filling rate.