Abstract
The two-group interfacial area transport equations (IATE) are coupled with an existing three dimensional three-field two-fluid model for adiabatic flow simulations in the bubbly-cap bubble regime. The mechanisms of the two-group IATE bubble interactions that have been proposed and validated in the past for one dimension are extended to a multi-dimensional model. The CFD simulations were validated using the data of Sun et al. [1] where the phase distribution, interfacial area concentration and velocity distribution in the cross-section for small and cap bubbles were measured separately using the four-sensor conductivity probe at four axial locations. The results demonstrate that the coupling is feasible. An interfacial turbulent diffusion force constitutive relation is modified and a new mechanism for inter-group bubble transport is identified and constituted.