Interfacial structures and regime transition in co-current downward bubbly flow

The vertical co-current downward air-water two-phase flow was studied under adiabatic condition in round tube test sections of 25.4-mm and 50.8-mm ID. Inflow regime identification, a new approach was employed to minimize the subjective judgment. It was found that the flow regimes in the co-current downward flow strongly depend on the channel size. In addition, various local two-phase flow parameters were acquired by the multisensor miniaturized conductivity probe in bubbly flow. Furthermore, the area-averaged data acquired by the impedance void meter were analyzed using the drift flux model. Three different distributions parameters were developed for different ranges of non-dimensional superficial velocity, defined by the ration of total superficial velocity to the drift velocity.