Modeling of pulverized coal combustion with non-gray gas radiation effects

A numerical study for simulating a swirling pulverized coal combustion in a xisymmetric geometry is carried out here by applying the weighted sum of gr ay gases model (WSGGM) approach with the discrete ordinate method (DOM) to model the radiative heat transfer equation. In the radiative transfer equat ion, the same polynomial equation and coefficients for weighting factors as those for gas are adopted for the coal/char particles as a function of par tial pressure and particle temperature. The Eulerian balance equations for mass, momentum, energy, and species mass fractions are adopted with the sta ndard k-epsilon turbulence model, whereas the Lagrangian approach is used f or the particulate phase. The eddy-dissipation model is employed for the re action rate for gaseous mixture, and the single-step first-order reaction m odel for the devolatilization process for coal. By comparing the numerical results with experimental ones, the radiation model used here is confirmed and found to provide sound alternative for simulating radiative characteris tics.