Bubble sizes produced by shear and turbulence in a bubble column

Abstract Measurements of bubble sizes for co-current upward air-water flow in a recirculating loop bubble column are described. The bubble sizes were determined with a two electrode conductivity detector. The effectiveness of two different designs of baffle in reducing the bubble size is assessed. The first type of baffle was a perforated plate placed across the air-water flow, which broke the bubbles by the shear flow and turbulence it caused. The measurements with this type of baffle are consistent with a recently developed theory of bubble break-up in shear flow. The second type of baffle consisted of a series of wire arrays placed across the flow. These broke the bubbles by a cutting action. The rate of bubble coalescence downstream of this baffle was determined, over a range of gas hold-up.