BUBBLE FORMATION AT SUBMERGED NOZZLES FOR SMALL GAS-FLOW RATE UNDER LOW GRAVITY

To develop gas-liquid contacting processes in space stations, bubble f ormation at a nozzle submerged in liquid under low gravity was discuss ed. Effects of gas flow rate and surface tension on bubble formation w ere experimentally investigated over a 10 s period using the drop shaf t of Japan Microgravity Center at Kamisunagawa in Japan. When the gas flow rate is comparatively small, a spherical bubble does not detach f rom the nozzle and continues to expand in quiescent liquids. To theore tically describe bubble formation under low gravity, the non-spherical bubble formation model was used. It is predicted by this model that b ubble volume increases under constant flow conditions and a bubble doe s not detach from a nozzle when the gas flow rate is small in a quiesc ent liquid. These calculated results of bubble volume and shape agree well with the experimental ones. (C) 1997 Elsevier Science Ltd.