A study of adiabatic two-phase flows using the two-group interfacial area transport equations with a modified two-fluid model

•The two-group IATE is implemented into a CFD code, ANSYS CFX.•A combined gas momentum equation is solved for two groups of bubbles.•New models are developed for lift and bubble-induced turbulent diffusion forces.•New bubble-induced turbulence model is considered.

The dynamic development of interfacial structure in two-phase flows has been studied by using the interfacial area transport equations with various bubble interaction mechanisms. The two-group interfacial area transport equations are incorporated into a multiphase computational fluid dynamics code in the framework of the two-fluid model which is modified to use a combined gas momentum equation for two groups of bubbles. A benchmark is performed for adiabatic churn-turbulent and cap-turbulent flows in a confined vertical rectangular duct (20 cm × 1 cm) with newly developed hydrodynamic models for lift and bubble-induced turbulent diffusion forces as well as the bubble-induced turbulence. The benchmark results demonstrate improved predictive capability of the two-fluid model with these hydrodynamic models and the two-group interfacial area transport equations.