Modelling of Heating and Evaporation of Gasoline Fuel Surrogate Droplets

The results of modelling of the heating and evaporation of several gasoline surrogate droplets are reported. Five fuel mixtures are considered with the following initial liquid molar fractions: FACE (Fuel for Advanced Combustion Engines) A: 7% n-butane, 15% iso-pentane, 11% 2-methylhexane, 7% n-heptane, and 60% iso-octane; FACE C: 17% n-butane, 8% iso-pentane, 5% 2-methylhexane, 11% n-heptane, 3% toluene, and 56% iso-octane; PRF (Primary Reference Fuel) 84: 17.6% n-heptane and 82.4% iso-octane; PRF 100: 100% iso-octane and PRF 0: 100% n-heptane. The analysis is based on the Effective Thermal Conductivity/Effective Diffusivity (ETC/ED) and Infinite Thermal Conductivity/Infinite Diffusivity (ITC/ID) models. The ETC/ED model takes into account the effect of finite thermal conductivity, finite liquid diffusivity and recirculation inside droplets. Also, this model takes into account the effect of internal circulation in the moving droplets. The ITC/ID model ignores these effects. It is pointed out that the evaporation time of n-heptane droplets is the longest. Droplet temperatures predicted by the ETC/ED model differ significantly from those predicted by the ITC/ID model. The predicted temperature and mass fraction distributions highlight the practical importance of the ETC/ED model when studying the heating and evaporation of multi-component droplets.