Numerical Modelling of Devolatilization in Pulverised Coal Injection Inside a Hot Coflowing Air Flow

A two-dimensional separated flow model has been developed for predicting fluid-particles turbulent recirculating two-phase flows. Thus, separate conservation equations are formulated for both phases including interphase transfer terms (mass, momentum and enthalpy). Turbulence is modeled by means of a q2- ɛ eddy viscosity model in the continuous phase which does not, at the present, take account for the interaction between the two phases.The model, including pyrolysis of coal and combustion of volatile matter, is used to compute an axisymetric injection of pulverised coal in a hot coflowing air flow, for two different particle sizes and two different inlet temperatures of the coflowing air flow. A first attempt is made to model the heterogeneous gaseous combustion process due to the local distribution of matter around particles.