Abstract:

A new partial spectrum k -distribution model is developed for oxy-fired boilers, characterized by larger pressure path-lengths and possibly different ratios of water vapor and carbon dioxide compared to air-fired boilers. In this model spectral regions with similar background properties are grouped into M partial spectrum distributions, in which the k distribution absorption coefficients of mixture are produced from multiplication approach. The absorption coefficients of gas are assembled from a narrow-band k -distribution database, but the scattering and absorption coefficients and phase function of particle are predicted by Mie theory. The radiation source and wall flux between two cold black parallel plates and for one signal spectral path and a two-dimensional rectangular system are calculated to verify the present model by combination of the present model and the discrete ordinate method in the furnace of flue gas with soot, flyash, high concentration of water vapor and carbon dioxide gas under oxygen-enriched coal combustion mode. The results from the present mode are more reasonably consistent with those by the line-by-line method. Moreover, the accuracy of the present model is higher and the computation time is reasonable compared with full-spectrum correlated- k distribution and wide band correlated- k model. It seems that this new partial spectrum k -distribution model is suitable for oxygen-enriched flue gas with flyash.