An application of Spectral line-based weighted sum of grey gases (SLW) model with geometric optics approximation for radiative heat transfer in 3-D participating media

A three-dimensional radiation code based on method of lines (MOL) solution of discrete ordinates method (DOM) coupled with spectral line-based weighted sum of grey gases (SLW) model and geometric optics approximation for particles is developed and its predictive ability is tested by applying it to the freeboard of a 0.3 MWt Atmospheric Bubbling Fluidized Bed Combustor (ABFBC) containing a non-grey, absorbing, emitting and isotropically scattering particle laden flue gas and comparing its predictions with measurements and former predictions obtained by the grey gas model with Mie theory for particles. The MOL of DOM with SLW and geometric optics assumption are found to provide more accurate solutions for incident radiative heat flux than grey gas model with Mie theory particularly for high particle loading. Parametric studies are also carried out to investigate the effect of size parameter and presence of particles on fluxes. MOL–SLW predictions are found to be sensitive to both the size parameter and particle load.