Thermal diffusivity wall function in simulations of turbulent channel flow with droplet condensation

Abstract

The latent heat of the phase transition provides an intrinsic link between heat and mass transfer in flows with condensation. In many of these flows, from heat exchangers to large-scale atmospheric convection, the heat transfer rates are modified due to phase change effects. However, including especially dropwise condensation in numerical flow simulations remains challenging, with insufficient accuracy in simplified models on one end of the spectrum and high computational costs in fully resolved direct numerical simulations on the other end. In this work, we investigate a condensation wall model using a scaled thermal diffusivity regarding its predictive capabilities in DNS of turbulent channel flow in comparison to the super-droplet approach.