A numerical simulation of spontaneous ignition of bagasse

摘要

This paper presents a numerical study of spontaneous ignition of a bagasse cube basket inside a convective oven. The study considered a cubic bagasse mass as a porous medium allowing oxygen from the surroundings to diffuse into and react with the interior of the bagasse matrix. A set of coupled partial differential equations of heat and mass transfer was solved numerically with a well-known CFD software package, ANSYS FLUENT. The simulated results were then compared with experimental measurements. In general, good agreement between the simulated and measured centre temperatures of a cubic bagasse basket was obtained. Simulation results demonstrated that as the cubic bagasse basket size and its initial moisture content increased the spontaneous ignition time increased. Alternatively, decreasing the porosity increased the spontaneous ignition time. The differences between 2D and 3D simulation results were also investigated. It was found that the simulated centre temperature in the 3D simulation was slightly higher than that obtained from 2D calculations.