TPG-7 Challenges of Simulating Complete Intube Phase Change with CFD

K. J. Farrell

Over the past several decades, the accuracy and usability of computational methods have substantially improved. This report reviews the complicated physics of two-phase flow and phase change, presents the equations of motion for a two-phase flow with various closure models, and compares current computational approaches. Although inadequate for the entire spectrum of flow regimes encountered during complete condensation or vaporization, these numerical models are valid for a specific two-phase configuration over a limited range of process conditions. The relatively new and evolving lattice Boltzmann method can potentially compute flows with total phase change through various flow regimes, allowing sufficient spatial and temporal resolution to observe and even optimize heat transfer effects at a tailored surface. The fundamentals of this method and the remaining challenges are described in simple terms.