Impact of corrected activity coefficient on the estimated droplet heating and evaporation

The paper presents a revised model of multi-component droplet heating and evaporation, in which a correction to the saturated pressure, using the activity coefficient, is proposed. This model is based on the previously developed version of the Discrete Component model (DCM), using the analytical solution to heat transfer and species diffusion equations inside droplets. The universal quasi-chemical functional group activity coefficients (UNIFAC) model is used to predict the activity coefficient for the components of diesel and gasoline fuels. It is found that the droplet evaporation time and surface temperature predicted for these fuels show noticeable differences from those estimated using the conventional DCM in literature. The results indicate that the use of the classical DCM approach can expose the estimation of droplet lifetime to errors of up to 4% for diesel fuel and 2.6% for gasoline, compared to the predictions of the same model using the proposed correction.