IGNITION AND PROPAGATION OF LAMINAR SPRAY FLAMES

Abstract

It is necessary to gain better knowledge about the characteristics of spray flame, such as the minimum ignition energy (MIE), flame propagation speed, and flame front/droplet interaction. In this thesis, theoretical and numerical methods are utilized to study those characteristics in laminar spray flames. Firstly, propagation of one-dimensional planar flames laden with fuel droplets is theoretically investigated. Secondly, propagation of weakly stretched spherical flames in partially pre-vaporized fuel sprays is theoretically studied. Thirdly, evolution of the fuel droplet evaporation zone and its interaction with propagating flame front are studied theoretically. Furthermore, forced ignition of ethanol droplets/vapor/air mixtures is numerically simulated. Finally, this thesis numerically investigates the forced ignition and oscillating propagation of spray flame in a mixture of fine ethanol droplets and air. Good agreement is shown between theoretical prediction and numerical simulation. Moreover, the results obtained from the two methods provide comprehensive knowledge about the characteristics of spray flames.