Abstract: During the long time on-orbit operation of space cryogenic propellant tanks, the continuous evaporation of cryogenic propellant in the tanks due to heat leakage from the wall surface causes the pressure in the tanks to rise continuously (i. e. the self-pressurization phenomenon), jeopardizing the safety of the tanks and the spacecraft. In order to prevent large liquid sloshing, large-scale spatial tanks are equipped with sloshing-suppression barriers, which may have a significant impact on the gas-liquid flow and heat transfer inside the tank. In this paper, the effect of the near-wall barrier on the gas-liquid two-phase flow and its thermodynamic process in the storage tank is numerically simulated using the VOF method, in order to reveal the mechanism of the effect of the sloshing-suppression barrier on the self-pressurization process of the storage tank. Numerical simulation results of liquid sloshing and thermodynamic characteristics in partially liquid-filled storage tanks with and without near-wall barriers in different gravity environments show that: the liquid surface configuration in the tank is determined by the Bond number, and the liquid surface basically stays flat in the condition of Bond number much larger than 1, while the liquid surface climbs along the wall of the tank in the case of Bond number less than 1; near-wall sloshing-suppression barriers can significantly reduce the fluctuation of the center of mass of the fluid in the tank; when the near-wall sloshing-suppression barrier is located below the liquid surface, it can hinder the rise of liquid warming in the near-wall area, which makes the liquid surface temperature in the near-wall area low, and the self-pressurization rate is obviously lower than that of the storage tank without a barrier. Finally, based on the simulation analysis and comparison of the effect of the near-wall barrier size, the recommended configurations of the near-wall sloshing-suppression barriers under different gravity conditions are given. The results of the study can provide a valuable reference for the program design of fluid management technology for space tanks.

Key words: space cryogenic propellant tank, self-pressurization, near-wall baffle, microgravity, numerical simulation