Influence of forward scattering on prediction of temperature and radiation fields inside the pulverized coal furnace

A possibility of simplification of the scattering phase function of a pulverized coal flame was analyzed in the paper. It was showed that the type of radiation scattering of a pulverized coal flame is between two limiting cases: isotropic and forward scattering. A comprehensive mathematical model of a tangentially fired furnace by pulverized coal was formed. Radiative heat transfer was modeled using the six-flux model. Grid independent results of the numerical simulations were obtained. The mathematical model was verified by comparison of the results of numerical simulations with results of measurements. The influence of the type of radiation scattering on results of numerical simulation was analyzed through the relative and average differences of the gas-phase temperatures, the total radiation fluxes, and the absorbed wall fluxes of the left furnace wall. The investigation showed that the total radiation fluxes were considerably influenced by the type of radiation scattering. On the other hand, the gas-phase temperatures and the absorbed wall fluxes were much less influenced by the type of radiation scattering. The results justify the use of the scattering phase function corresponding to isotropic scattering in radiation models of comprehensive mathematical models of pulverized coal fired furnaces.

► Simplification of scattering phase function is studied.
► Comprehensive mathematical model of tangentially fired furnace is used.
► Six-flux model of thermal radiation is used.
► Investigation justifies use of scattering phase function for isotropic scattering.