Free surface bubbly flow in an open capillary channel.

This study investigates bubbly flow in a rectangular open channel under microgravity. A homogeneous flow model is used to compute frictional pressure loss and then establish a correlation between the drag coefficient and mass quality, leading to a one-dimensional model of free surface bubbly flow. Furthermore, the homogeneous flow model is integrated into computational fluid dynamics simulations, which align closely with experimental observations. The theoretical model and simulations show a strong concordance, with a critical flow rate determined through calculations exhibiting an average relative error of 4.93%. The findings reveal a positive correlation between mass quality and critical flow rate; increasing mass quality enhances the critical flow rate and stabilizes the free surface but reduces the liquid phase's flow efficiency. This research contributes to the theoretical understanding of microgravity free surface flow.