Analytical model of the inuence of recirculation on premixed combustion of lycopodium dust particles: A study of thermal resistance and random distribution of particles

Abstract

In the present study, a comprehensive analytical method was developed to model ame propagation through organic particles with air as a two-phase mixture, considering random distribution and particles thermal resistance. For this purpose, the structure of ame contained a preheat-vaporization zone, a reaction zone where vaporization and convection rates of particles were negligible, and a post ame zone where diffiusive terms were negligible in comparison with the zone for other terms. In order to enhance combustion efficiency, the exhausted heat from the post ame zone was recirculated back to the preheat zone. Since the stream consisted in a high-temperature gaseous mixture, it could enhance the temperature of the initial two-phase mixture entering the combustion chamber. A reasonable agreement between the results of the analytical approach and the experimental findings was obtained. In addition to the random distribution of particles and heat recirculation phenomenon, the effect of thermal resistance on the combustion properties such as burning velocity and ame temperature was studied through non-zero Biot numbers in the proposed model. Moreover, the variations of several parameters including equivalence ratio, particle diameter, and Lewis number were investigated.