Transient Heating and Evaporation of Moving Fuel Droplets

In combustion devices involving direct injection of low-volatility liquid fuels (e.g., bio-oils from pyrolysis process), transient heating and vaporization of fuel droplets is a controlling factor in ignition and combustion of the fuel vapor/air mixture. As a result, some experimental and numerical efforts have been made on this topic. In this paper, a comprehensive 3D model that addresses the internal flow circulation, heat and mass transfer within a moving droplet has been successfully developed. The model is calibrated by analytical solutions for simplified cases and validated by experimental results available in literature. The model not only reliably produces all the details that help to achieve an in-depth understanding of the underlying physical processes and to derive simplified models for liquid fuel droplet heating and evaporation, but also can be readily reformulated for modeling of conversion of solid fuel particles.