Abstract:

The transient droplet high-pressure evaporation model including both sub- and super-critical mechanism is established based on the RK, SRK and PR real-fluid equation of states (EoS) respectively. The evaporation processes of the kerosene droplets under high-pressure nitrogen gas are studied numerically with emphasis on the effects of different EoS on the high-pressure vapor-liquid phase equilibrium of N 2 -C 12 H 26 binary system and high-pressure evaporation calculation aimed at high-pressure staged-combustion liquid oxygen/kerosene rocket engine. The results indicate that the most influencing parameter of the droplet evaporation rate is the mass fraction of vapor on the droplet surface, which is mainly affected by the chosen EoS. The calculated results of the high-pressure vapor-liquid phase equilibrium and high-pressure evaporation rate using both SRK and PR EoSs agree overall with the experimental data, and the evaporation characteristics at high pressure could be described well. In contrast, the results using the RK EoS over-predict mass fraction of vapor on the droplet surface and solubility of the ambient N 2 into the liquid phase, whereas under-predict the critical mixing temperature and partial molar heat of the phase change, consequently, over-predict the subcritical evaporation rate, whereas under-predict the supercritical evaporation rate. In addition, the minimum ambient temperature required for the trans-critical transition of the C 12 H 26 droplets based on RK EoS is lower than those based on SRK and PR EoSs.

Key words:  Liquid rocket engine, Kerosene droplet, High pressure evaporation, Vapor liquid phase equilibrium, Gas solubility.