Flamelet model for pulverized coal combustion

A new flamelet model applicable to the simulation of pulverized coal combustion has been developed. First, a modeling approach that considers the coupling with both devolatilization and char combustion was adopted. We changed the fuel composition of the flamelet equation relative to the states of devolatilization and char combustion. In order to determine the fuel composition coming through the char combustion, all the gasified char was assumed to be converted into CO by the oxidation reaction. The validity of the developed flamelet model was examined in a simple two-dimensional pulverized coal jet field ignited by burnt co-flows. The accuracy of the model was evaluated by comparing its instantaneous distributions of temperature, CO2 mass fraction, and OH mass fraction with those of a detailed chemistry model. Good agreement was obtained in terms of the overall features of turbulent structures and combustion state, although the flamelet model showed slightly quicker ignition due to the transitional state in the ignition process being insufficiently reproducible. (C) 2014 The Combustion Institute. Published by Elsevier Inc. All rights reserved.