Numerical study of micro-explosion delay of water-in-fuel emulsion droplets
Résumé
Spray combustion of water-emulsified fuel induces an effective decrease in total combustion time, carbonaceous residues and NOX compared to pure fuel, thanks to the micro-explosion phenomenon. Designing emulsion-burning appliances requires to calculate the micro-explosion delay included in total combustion time. This rather technical contribution addresses the problem of how to model the process of microexplosions in emulsions. The authors describe a numerical method to account for thermal conduction effects and analyze its effect upon the microexplosion delay. Some of the expressed physical quantities may be useful for other researchers in this field. The evolution of the emulsion droplet (radius and temperature through the time) is faced with experimental micro-explosion delay, for three cases of emulsion droplet (different initial diameters and temperatures). Finally, observations resulting from this comparison are discussed.