Hydrodynamics of large attached bubbles in a downward liquid flow

Stationary gas slug attached to the gas sparger in the downcomer of an air- lift fermenter can cause serious operational problems. The results of exper imental investigation on the influence of liquid and gas flow rates on the behaviour of an attached bubble formed in a vertical pipe have been present ed. The size distribution of the bubbles shed from the gas slug base in the mixing zone has also been measured and correlated with the mean energy dis sipation rate in the zone.