Unified Modeling Suite for Two-Phase Flow, Convective Boiling, and Condensation in Macro- and Microchannels

This paper focuses on the unified modeling suite for annular flow that the authors have developed and continue to develop. The annular flow suite currently includes models to predict the void fraction, the entrained liquid fraction, and the wall shear stress and pressure gradient, and a turbulence model for momentum and heat transport inside the annular liquid film. The turbulence model, in particular, allows prediction of the local average liquid film thicknesses and the local heat transfer coefficients during convective evaporation and condensation. The benefit of a unified modeling suite is that all the included prediction methods are consistently formulated and are proven to work well together, and provide a platform for continued advancement based on the other models in the suite. First the unified suite of methods is presented, illustrating in particular the most recent updates. Then results for the pressure drop and the heat transfer coefficient during convective evaporation and condensation are presented and discussed, covering both water and refrigerants flowing through circular tubes and noncircular multi-microchannel configurations for microelectronics cooling.