Modelling of fuel droplet heating and evaporation: Recent results and unsolved problems

The most recent developments in the modelling of heating and evaporation of fuel droplets, the results of which were published in 2014–2017, are reviewed, and the most important unsolved problems are identified. Basic principles of power law and polynomial approximations and the heat balance method for modelling the heating of non-evaporating droplets are discussed. Several approaches to modelling the heating of evaporating droplets, predicting different heating and evaporation characteristics, are compared. New results in modelling heating and evaporation of spheroidal droplets are identified. Basic principles of the Discrete Component Model and its application to biodiesel fuel droplets are summarised. Main ideas of the Multi-dimensional Quasi-discrete Model and its applications to Diesel and gasoline fuel droplets are discussed. New developments in gas phase evaporation models for multi-component fuel droplets are presented. A self-consistent kinetic model for droplet heating and evaporation is described. New approaches to the estimation of the evaporation coefficient, including those taking into account quantum-chemical effects, are summarised. Among unsolved problems, the effects of non-spherical droplets, limitations of the ETC/ED model, effects of the interaction between droplets, effects of the moving interface due to evaporation, modelling of complex multi-component droplets, modelling of droplet heating and evaporation in near- and super-critical conditions, development of advanced kinetic and molecular dynamics models and effective approximation of the kinetic effects are discussed.