On the numerical study of bubbly flow created by ventilated cavity in vertical pipe

The dispersion of bubbles into a down-liquid ?ow in a vertical pipe is investigated. At low ?ow rates, the intended design of a swarm of discrete bubbles is achieved. At high ?ow rates, a ventilated cavity is nonetheless formed, which is attached close to the gas sparger. Behind this ventilated cavity, three different ?ow regimes characterize the complex bubbly ?ow ?eld downstream of the down-liquid ?ow: vortex region with high void fraction, transitional region and pipe ?ow region. In this study, a numerical model that solved the entire development of the gas¿liquid ?ow including the extended single-phase liquid region upstream to the wall-jet and recirculating-vortex zones in order to allow a more realistic determination of the boundary conditions of the down-liquid flow was adopted.