Investigation of biomass combustion systems using CFD techniques: a parametric study of packed-bed burning characteristics

In this paper, mathematical equations governing the fluid flow, heat and mass transfer and heterogeneous reactions in packed-bed combustion systems are described and sub-models for individual processes are presented. A model estimating the mixing rate between the under-grate air and the released volatile gases is described. Parametric study was carried out to assess the effects of fuel moisture content, kinetic rate of devolatilisation, primary air flow rate and particle mixing levels caused by grate movement. Useful conclusions were drawn in terms of flame temperature, reaction zone thickness, mass loss rate, combustion staging and residual carbon in ash.