Abstract：A numerical method is developed based on the conservation equations for multicomponent reacting systems to better predict char particle combustion. The advantage of this method is that many physical and chemical processes occurring in the char particle boundary layer are described in detail with less CPU time, which improves the studies of the char combustion mechanism. This method can also be used to simulate real situations with relatively simple flow patterns, like the char particle combustion in a drop tube furnace (DTF). Four chars are combusted in a DTF with their final conversions measured. The predicted char conversions compare well with the measured data to validate this method. As the ambient temperature increases, the char combustion rate becomes faster and the O2 concentration decreases while the CO and CO2 amounts strongly increase in the char particle boundary layer.
刘雨廷, 何榕. 单颗粒煤焦在大空间中燃烧的数值模拟方法及实验验证[J]. 清华大学学报（自然科学版）, 2016, 56(6): 598-604.
LIU Yuting, HE Rong. Numerical simulation method and experimental validation of a single char particle combustion model in bulk space. Journal of Tsinghua University(Science and Technology), 2016, 56(6): 598-604.
 Chen L, Yong S Z, Ghoniem A F. Oxy-fuel combustion of pulverized coal: Characterization, fundamentals, stabilization and CFD modeling [J]. Progress in Energy and Combustion Science, 2012, 38(2): 156-214.
 He W, He R, Cao L, et al. Numerical study of the relationships between pore structures and reaction parameters for coal char particles [J]. Combustion Science and Technology, 2012, 184(12): 2084-2099.
 Chen Y, He R. Fragmentation and diffusion model for coal pyrolysis [J]. Journal of Analytical and Applied Pyrolysis, 2011, 90(1): 72-79.
 He W, Liu Y, He R, et al. Combustion rate for char with fractal pore characteristics [J]. Combustion Science and Technology, 2013, 185(11): 1624-1643.
 Smith I W. The combustion rates of coal chars: A review [J]. Symposium (International) on Combustion, 1982, 19(1): 1045-1065.
 Geier M, Shaddix C R, Davis K A, et al. On the use of single-film models to describe the oxy-fuel combustion of pulverized coal char [J]. Applied Energy, 2012, 93: 675-679.
 Turns S R. An Introduction to Combustion: Concepts and Applications [M]. 2nd Ed. Boston, MA: McGraw-Hill, 2000.
 Avnir D, Farin D, Pfeifer P. Surface geometric irregularity of particulate materials: The fractal approach [J]. Journal of Colloid and Interface Science, 1985, 103(1): 112-123.
 Everson R C, Neomagus H W J P, Kaitano R. The random pore model with intraparticle diffusion for the description of combustion of char particles derived from mineral-and inertinite rich coal [J]. Fuel, 2011, 90(7): 2347-2352.
 Paviet F, Bals O, Antonini G. The effects of diffusional resistance on wood char gasification [J]. Process Safety and Environmental Protection, 2008, 86(2): 131-140.
 Zhang M, Yu J, Xu X. A new flame sheet model to reflect the influence of the oxidation of CO on the combustion of a carbon particle [J]. Combustion and Flame, 2005, 143(3): 150-158.
 Bejarano P A, Levendis Y A. Single-coal-particle combustion in O2/N2 and O2/CO2 environments [J]. Combustion and Flame, 2008, 153(1/2): 270-287.
 Kuo K K. Principles of Combustion [M]. 2nd Ed. New York, NY: John Wiley and Sons, 2005.
 He W, He R, Ito T, et al. Numerical investigations of CO/CO2 ratio in char combustion [J]. Combustion Science and Technology, 2011, 183(9): 868-882.
 Howard J B, Williams G C, Fine D H. Kinetics of carbon monoxide oxidation in postflame gases [J]. Symposium (International) on Combustion, 1973, 14(1): 975-986.
 He R, Sato J, Chen C H. Modeling char combustion with fractal pore effects [J]. Combustion Science and Technology, 2002, 174(4): 19-37.
 He R, Xu X C, Chen C H, et al. Evolution of pore fractal dimensions for burning porous chars [J]. Fuel, 1998, 77(12): 1291-1295.
 Tognotti L, Longwell J P, Sarofim A F. The products of the high temperature oxidation of a single char particle in an electrodynamic balance [J]. Symposium (International) on Combustion, 1991, 23(1): 1207-1213.
 Annamalai K, Ryan W. Interactive processes in gasification and combustion, II: Isolated carbon, coal and porous char particles [J]. Progress in Energy and Combustion Science, 1993, 19(5): 383-446.
 He R, Suda T, Fujimori T, et al. Effects of particle sizes on transport phenomena in single char combustion [J]. International Journal of Heat and Mass Transfer, 2003, 46(19): 3619-3627.