Effect of asymmetric radiant heating on monodisperse acetone/ethanol and acetone/2-propanol bi-component droplets

Abstract

Fuel droplet vaporization is an integral element ofmany combustion systems and extensive research has been carried out in the field to explore and model the droplet heating and vaporization process. Many numerical and most experimental droplet studies have considered isolated droplets or a stream of droplets exposed to uniform and symmetric vaporization conditions. However, few numerical and even fewer experimental studies have addressed the influence of radiant heating on droplet vaporization. In particular, there are likely to exist combustion environments where radiant heating is both non-negligible as well as asymmetric. Asymmetric radiant heating of droplets may exist in counter-flow, liquid-fuelled diffusion flames, conventional spray flames, and in liquid-fuelled microcombustors. Ammigan et al. (in press) provides a review of droplet vaporization literature with a focus on radiant heating. Recent works by the authors have considered single component (acetone) (Ammigan and Clack, 2009) and bi-component (acetone and hydrocarbons octane and hexane) (Ammigan et al., in press) droplets vaporizing under asymmetric thermal radiation. PLIF images consistently revealed that acetone vapor mole fraction distributions on the irradiated side were punctuated by local concentration maxima, whose extent varied with droplet composition, diameter, and incident radiant flux. Such behavior is the result of localized radiant heating of the droplet and the influence of droplet thermophysical properties and the phase equilibria of the droplet