Fuel Processing Technology, Vol.179, 184-196, 2018
Theoretical study of non-adiabatic counter-flow diffusion flames propagating through a volatile biomass fuel taking into account drying an vaporization processes
Due to important advantageous of non-premixed flames such as controllability and safety, a proper investigation can be highly beneficial for application of these flames in medical and power generation industries. The current paper attempts to provide a promising analytical model for non-adiabatic counter-flow diffusion flames propagating through volatile biomass particles using an asymptotic method. In order to offer a reliable model for analysis of the flames, a multi-zone flame structure including preheat, drying, vaporization, reaction and oxidizer zones, is considered. In this work, lycopodium particles and air are taken as biofuel and oxidizer, respectively. For following the influences of effective dimensionless numbers, such as fuel and oxidizer Lewis numbers on the flame structure, dimensionalized and non-dimensionalized forms of mass and energy conservation equations are derived for each zone. In order to observe the heat loss effects, a linear term is added to the energy conservation equation. The conservation equations are solved by Mathematica and Matlab software applying accurate boundary and jump conditions. Finally, variations of flame temperature, flame front position, gaseous fuel and oxidizer mass fractions with fuel and oxidizer Lewis numbers, mass particle concentration, particle size, equivalence ratio and heat loss effect are elaborately elucidated.