Bubble formation at submerged nozzles for small gas flow rate under low gravity

To develop gas-liquid contacting processes in space stations, bubble formation at a nozzle submerged in liquid under low gravity was discussed. Effects of gas flow rate and surface tension on bubble formation were experimentally investigated over a 10 s period using the drop shaft of Japan Microgravity Center at Kamisunagawa in Japan. When the gas flow rate is comparatively small, a spherical bubble does not detach from the nozzle and continues to expand in quiescent liquids. To theoretically describe bubble formation under low gravity, the non-spherical bubble formation model was used. It is predicted by this model that bubble volume increases under constant flow conditions and a bubble does not detach from a nozzle when the gas flow rate is small in a quiescent liquid. These calculated results of bubble volume and shape agree well with the experimental ones.