Molecular dynamic modeling of supercritical lox evaporation

The complete evaporation of a three-dimensional submicron oxygen droplet into quiescent environments has been simulated using molecular dynamics. The environments were comprised of either hydrogen or helium and pressures ranged from 2-20 MPa. Droplet evaporation rates and thermodynamic property profiles were obtained. Results show that at low to moderate pressures the droplet remains spherical throughout the evaporation and retains a distinct temperature profile. This is referred to as subcritical evaporation behavior. At high pressures the droplet evaporates in a cloud-like manner with vanishing surface tension, which is called supercritical evaporation behavior. The environment pressures required to cause transition to supercritical evaporation behavior were well above the pure species' critical pressures, which suggests very high mixture critical pressures for the systems studied.