Gas–Liquid Transport Behaviors and Mass Transfer Mechanism During Oxygen Dissolution and Evolution Processes in a Micropump

On-orbit refueling and space circulation technologies involve the use of a space micropump to transport gas-liquid mixed fluids, which affects the gas-liquid mass transfer and dynamic behaviors. To predict dynamic mass transfer processes, our proposed dissolved and released models were applied to space micropump calculation after the verification of dissolved oxygen concentration and micropump energy characteristics. The mass transfer characteristics and gas-liquid states were investigated by combining the correlation analyses. The results show that the dissolved concentration and the volume fraction are considered to be strongly related to the mass transfer rate, and the effect of turbulence kinetic energy cannot be ignored particularly in the impeller and volute. Based on this, the gas-liquid state parameters are focused on unidirectional dissolved and bidirectional released-dissolved conditions. The released gas occupied the head of the suction surface of the long blades and developed downstream, and its presence causes a significant gas increase downstream. According to the mass-transfer characteristics comparisons, the oxygen increment decreases as the inlet dissolved oxygen concentration increases, exhibiting the similarity of the two-film theory. In addition, the evolution increases the fluctuation in the gas volume fraction and the total hydraulic loss. The current study guides the fueling gas-liquid mixed delivery status, and the dissolved gas concentration must be controlled strictly to avoid the evolution of gas to ensure safety and decrease the flow loss.