DNS of evaporating turbulent two-phase flows with resolved liquid-gas interface

Recent advances in interface tracking method allows us to use them as a tool to study primary atomization. Some recent works have performed accurate Direct Numerical Simulation of turbulent liquid jets which are very promising. Unfortunately, one main topic about primary atomization have not been taken into account in these simulations: the vaporization process. It can be one of the most important process in many fields (e.g. combustion). This study focuses on the evaporation and mixing process in turbulent two-phase flows with a direct resolution of the flow near the interface. A first approach, using a passive scalar to represent the evaporation and mixing process in a two-phase dense turbulent flow, has been developed and applied in a homogeneous isotropic turbulence over a large range of liquid volume fractions. This model is restricted to low vaporization rates, thus the interface is barely affected by the evaporation process. A statistical analysis of the vapor field is performed. Obtained results suggest that the beta PDF, frequently used in combustion modeling, are not adequate to represent the state of scalar mixing when interfaces are taken into account.