Mathematical analysis of steady-state non-premixed multi-zone combustion of porous biomass particles under counter-flow configuration

Abstract

In this study, non-premixed multi-zone combustion of porous lycopodium particles in a counter-flow configuration at steady state was modeled using a derived analytical model. To model the porosity, a reasonable series form is considered. In the derived analytical model, both convective and radiative heat losses were included. The overall combustion process was mathematically divided into pre-heating, drying, vaporization, flame, and post-flame zones and lycopodium particles and oxidizer are injected from opposite sides locating infinity away the stagnation plane. The particles are firstly dried and then vaporized in a limitedly finite region to produce a gaseous fuel of special chemical composition. Relevant conservation equations were formulated in both dimensional and dimensionless forms. Applying suitable jump and boundary conditions, the corresponding continuity and energy equations were solved using Mathematica and Matlab software. The derived analytical model was first validated through comparison against literature data and a satisfactory agreement was achieved. Then temperature distribution and mass fractions of fuel and oxidizer along the x direction were presented to describe the combustion characteristics. Finally, a series of parametric studies were conducted to study the effects of key operating conditions. • Non-premixed combustion of biomass in counter-flow design is analytically simulated. • Porosity of the organic fuel particles is modeled in detail using a simple series function. • Devolatilization of the biomass is mathematically modeled. • Combustion behavior of the combustion system fed with porous biomass is investigated under non-adiabatic conditions. • A series of parametric studies are conducted to study the effects of key operating conditions.