Abstract: In order to study the relationship between bubble motion characteristics and orifice gas inflow velocity or hole diameter under continuous gas supply conditions, we investigated the movement of the outlet bubbles in a still water. The bubble rise motion in still water simulated by using the OpenFoam of open source program is in consistence with experimental measurements. By adjusting the orifice gas inflow velocity and the hole diameter, we examined the detachment time and the diameter of the bubble and compared the difference of upward movement between initial spherical bubble and orifice outlet bubble. We proposed to describe the relationship between initial bubble velocity and gas inflow velocity by using relative velocity B of bubble motion. By using different dimensionless parameters, we predicted the value of B. Simulation and analysis results show that the We and Re numbers accurately predict the relative velocity B of bubble motion. The initial state of the bubble has a great influence on the trajectory of the bubble. The research results have further enriched the results in the related fields of bubble motion, and created ideas for the next step to finely characterize the complex motion of bubbles.

Key words: orifice outflow, OpenFoam, bubble detachment, bubble motion trajectory, relative velocity