Two-phase Numerical Study of Evaporation Characteristics of Moving Binary Droplets at High Pressures

This paper presents comprehensive numerical simulations of evaporation characteristics of droplets constituted of two liquid fuels moving and evaporating in a high pressure ambient that has fuel vapors and nitrogen gas under normal gravity. A transient, two-phase and axisymmetric numerical model has been used for the simulations. Gas-phase non-idealities, solubility of ambient gas in liquid-phase, and variable thermo-physical properties based on pressure and temperature in both liquid- and vapor-phases are included in the numerical model. High pressure phase equilibrium is used. The range of Weber number has been chosen such that droplet remains almost spherical throughout its lifetime. Simulations are terminated when the droplet surface regresses to one-tenth of its initial value or when the critical state for the mixture is reached. The model is used to systematically study the evaporation characteristics of moving n-heptane-hexadecane droplets in ambient having fuel vapor and nitrogen. The effects of the pressure and ambient vapor concentration on evaporation characteristics have been discussed in detail.