Temporally and Spatially Resolved Calculations of Particle Mixing in a Coal Jet Using Large Eddy Simulations (LES) and Direct Quadrature Method of Moments (DQMOM)

In turbulent coal jets, local particle and gas mixing distributions are critical for predicting flame characteristics and ultimately heat flux in a coal-fired boiler. The present work combines large eddy simulations (LES) with the direct quadrature method of moments (DQMOM) description of the number density function for the coal particle distribution in the near-burner region of a coal injector. When combined with the spatial and temporal resolution provided by LES, DQMOM yields a statistical description of the mixing behavior of the particle phase in the jet. Results are presented for a coal pyrolysis experiment. Three key particle behaviors are: particle segregation, particle clustering, and particle devolatilization. The present work identifies mixing issues relevant to combustion stability in reacting coal jets using LES and DQMOM.