A transient two-dimensional combustion model of a solid fuel bed that can be applied to various types of combustors employing the solid bed is presented in this work. Solid-gas reactions, gaseous reactions, heat transfer, changes in bed porosity and physical properties are modeled and envisaged in each term of the governing equations. A two-medium treatment is applied for the energy equation. The solid bed materials are homogenous whose contents include iron ore, limestone, coke and moisture. Numerical simulations have been done for various coke content 3.4%, 3.8%, 4.2%. Effects of various air supply rates 0.26, 0.32, 0.42, 0.46, 0.52 (m/s) have been investigated. Two different fuel particle diameters have been simulated. Also, effects of fuel substitution have been investigated. The simulation results were compared with the experimental data. Quantitative parameters are newly defined for characterization of the bed combustion. These include flame front speed, sintering time, duration time in the combustion zone, combustion zone thickness, melting zone thickness, and the maximum temperature. Relationships between these parameters and the mechanism of combustion propagation are also investigated. The results show quantitatively that temperature profiles, combustion propagation, and thickness of the combustion zone in the bed are dominated by combustion-related operating parameters. Key words Iron ore sintering bed, Fixed-bed combustion, Simulation, Solid fuel.
