Abstract: The transient droplet evaporation model including both sub-and super-critical mechanisms under high-pressure conditions was established on the basis of accurate prediction of the non-ideality of thermo-physical properties of the fluid using real-fluid models, as well as the high-pressure vapor liquid phase equilibrium of multi-components and the solubility of ambient gas into liquid phase using Equation of State (EoS) method. The evaporation characteristics of the kerosene droplet and the effect mechanisms of various factors on which under supercritical environments related to high-pressure staged-combustion liquid oxygen/kerosene rocket engine were studied. The results indicate that the subcritical evaporation state controlled by phase equilibrium was still behaved under weakly supercritical environment although the rise rate of droplet temperature was clearly enhanced under high-pressure conditions, whereas supercritical evaporation state controlled by diffusion appeared only under highly supercritical environment. The evaporation rate would be underestimated with ignoring the solubility of ambient gas under high-pressure and high-temperature conditions. Under the weakly supercritical environments, the rising ambient temperature would accelerate monotonically evaporation rate; the rising ambient pressure would suppress the evaporation rate under lower ambient temperature, whereas accelerate it under higher ambient temperature. In contrast, under the highly supercritical environments, the rising ambient temperature would accelerate the evaporation rate of the initial subcritical evaporation stage, whereas not affect the evaporation rate of the supercritical evaporation stage; the rising ambient pressure would also accelerate the evaporation rate of the initial subcritical evaporation stage, whereas suppress the evaporation rate of the supercritical evaporation stage, and the total lifetime of droplet would decrease slightly with the increase of ambient pressure.

Key words: kerosene droplet, high-pressure, evaporation, vapor liquid phase equilibrium, gas solubility, real-fluid model