Modeling of a Moving Reacting Carbon Char Particle Using Macropore-Resolved and Porous Media Approaches

This work presents a comparative computational study of the heterogeneous combustion of a single spherical carbon char particle in hot atmospheres with different O2 concentrations using a porous media model (PMM) and macropore-resolved simulations (PRS). A two-dimensional axisymmetric computational fluid dynamics model (2D CFD) in a pseudo-steady-state approach (PSS) is performed. In both cases, a semiglobal kinetic scheme is implemented, including three heterogeneous and three homogeneous chemical reactions. Several Reynolds numbers (Rein = 10, 50, and 100), inflow gas temperatures (Tin = 1100–2000 K), and inlet mass fractions of oxygen (YO2,in = 0.05 and 0.11) are assessed. Results show good agreement between PMM and PRS, especially for Tin = 2000 K, where the deviation in the values for the species was not higher than 8.3%. Maximum deviation for CO2 was 1.54% when evaluating the maximum values for the species concentration. In addition, the effects of the gasifying conditions, oxidative regime, and tortuosity on the partial oxidation process are discussed.