Droplet evaporation in a turbulent high-pressure freestream – A numerical study

This paper presents a 3D numerical model for predicting the evaporation of a droplet exposed to a turbulent, high-pressure and high-temperature gaseous nitrogen freestream. The governing complete set of time-dependent conservation equations of mass, momentum, energy, and species concentration for both gas- and liquid-phase are solved numerically. The turbulence term in the conservation equations of the gas-phase is modeled by using the shear-stress transport (SST) closure model. In addition, variable thermophysical properties, unsteadiness of the gas and liquid phases, radiation, non-ideal gas behavior, and solubility of gas into the droplet are all accounted for in the numerical model. A wide range of freestream conditions is explored. The present numerical predictions revealed that the freestream turbulence intensity still has an effect on the droplet vaporization even at significantly high-pressure and high-temperature conditions, although this effect weakens with an increase in both ambient pressure and temperature. More importantly, new correlations are proposed to account for the effects of freestream ambient conditions on the droplet vaporization process.