Investigation on Deformation of an Evaporating Droplet in Convective Transcritical Environments

An investigation of the dynamic deformation for an individual droplet under convective transcritical conditions is conducted with a developed deformation model. This model takes account of gas solubility in liquid phase, variable thermophysical properties, the effective conductivity accounting for convective heat and mass transfer and liquid phase internal circulation, and the disappearance of surface tension at the critical mixing point. The results show that (1) at higher ambient pressures, surface tension decreases more smoothly with the reduction of fuel mole fraction but more rapidly with the droplet surface temperature; (2) as time elapses, the drop is continuously oscillating, together with the decreasing oscillation amplitude; (3) at high ambient pressures and temperatures the maximum drop deformation occurs in the late stage of the evaporation process, while at low pressures and temperatures, it occurs in the initial stage. In addition, the drop deformation and Weber number are initially quite insensitive to the ambient temperature.