2013 Volume 55 Issue 172 Pages 94-109
Particle combustion of solid carbon in the quiescent atmosphere has been overviewed by use of accomplishment in the aerothermochemical analyses, in which not only the surface C-O2 and C-CO2 reactions but also the gas-phase CO-O2 reaction is taken into account. By virtue of the generalized species-enthalpy coupling functions, close coupling of those reactions has been elucidated. It has been identified that the combustion response in the three limiting situations, such as the Frozen, the Flame-detached and the Flame-attached modes, can be described analytically, by using the generalized coupling functions. Explicit combustion-rate expressions by use of the transfer number in terms of the natural logarithmic term, just like that for droplet combustion, have further been obtained for the combustion response in the limiting situations. In addition, by examining establishment of CO-flame over the carbon particle, it has been confirmed that the combustion rate can fairly be represented by the expression in the Frozen mode when the particle diameter is 100 μm or less. Since this expression is explicit and has fair accuracy, various contributions are anticipated not only qualitatively but also quantitatively. Combustion response in the transient situation has further been examined, from which an existence of the critical size for the particle burn-out has even been derived. A fair degree of agreement in experimental comparisons indicates that the present formulation has captured the essential features of the particle burn-out.
