Experimental and theoretical studies of the burning of small fuel particles

This chapter presents experimental and theoretical studies of the burning of small fuel particles. The degree of the overlapping of devolatilization and char combustion stages and fuel particle surface temperatures are important to measure in various conditions. The efflux flow of volatiles and the combustion of volatiles prevent the oxygen from reaching the particle surface, in cases where the devolatilization rate is rapid. It is found that when the devolatilization rate is great, no oxygen reaches the particle surface and the volatiles are combusted in the gas phase. In this case, the heat transfer from the gas to the particle and the combustion of volatiles in the gas phase can be studied by solving the energy equation and the conservation equations for volatiles, oxygen, and combustion products in the gas phase in a quasi-steady state. By assuming infinite gas phase kinetics, the solution becomes the infinitely thin flame sheet model.