Conditions of the Water–Coal Fuel Drop Dispersion at Their Ignition in the Conditions of High-Temperature Heating

Abstract

ABSTRACTThe results of a numerical analysis of the conditions and characteristics of the dispersion of the water–coal particles during ignition under the conditions of an intense radiation-convective heating have been presented in the article. A comparative analysis of the theoretical and experimental values of ignition delay times of the fuel particles has showed their good correlation. Also, a comparative analysis of the characteristic dispersion times, obtained theoretically and established in the experiments, has showed a good correlation between them. According to the results of the numerical simulation, it has been established that dispersion of the water–coal particles during their heating before their ignition can occur as a result of the occurrence of the filtration stresses in the porous structure of the fuel. It has been found that the dispersion of the particles occurs before a complete evaporation within the pore moisture.The theoretical analysis has shown that the permeability of a dry coal structure has a significant effect on the characteristics and dispersion conditions. The influence of the values of the dimensionless Darcy criterion (Da) on the dispersion conditions has also been analyzed. It has been established that as the value of Da increases, the dispersion time decreases substantially. This is due to a decrease in the permeability of the porous structure of the fuel.