Abstract
Bubble formation from an orifice at high gas injection rates was experimentally studied. At high gas injection rates, coalescence between growing and detached bubbles occurs. The coalescence is repeated approximately twice and the cycle of coalescence goes to completion. Coalescence between detached bubbles and the orifice becomes more or less continuous at very high gas injection rates; that is, a gas jet column is formed. The critical points for transition to the occurrence of coalescence and gas jet column are correlated by empirical equations.
The size of the non-coalesced first bubble formed at high gas injection rates is studied theoretically, based on the two-stage model obtained by authors previously by considering the force due to gas momentum through a hole, and a comparison with measurements is made.
