Study on the Lateral Sloshing Behavior under Microgravity Condition Targeted for a Propellant Tank

Fluid behavior in microgravity (µg) is different from in ground gravity since surface tension and wetting are dominant in µg conditions. In propellant tanks for artificial satellites and future on-orbit spacecraft, sloshing due to disturbance and settling behavior from changes in acceleration have to be understood for the design of the propellant supply system and attitude control system. In this paper, we observed sloshing behaviors in cylindrical containers in µg conditions created by a drop tower facility. In order to investigate the effects of the contact line velocity on dynamic contact angle, we measured dynamic contact angle using a capillary tube. CFD analysis introducing Cox’s equation in consideration of capillary experimental results were also conducted and these results were compared with µg experimental results. Regarding the experimental results, the diameter of the test tank, excitation acceleration, and kinematic viscosity were found to have a significant effect on sloshing behavior in a µg condition. Regarding the comparison between the CFD analysis results and the experimental results, there was a slight difference in the wave shape and the time required for the liquid to reach the top of the test tank. Conversely, there was a qualitative agreement between the fluctuation period and the approximate shape of the liquid surface over time