A wavenumber subinterval grouping strategy compatible with non-gray metal wall boundaries used in multi-scale multi-group full spectrum k-distribution gas radiation model

In the present work, strategies for the grouping of wavenumber subintervals were extended to deal with the compatibility of multi-scale multi-group full-spectrum k-distribution model with non-gray wall boundaries. The main idea is to enhance the correlated-k characteristics of absorption spectra of H₂O-CO₂ mixtures and emission spectra of non-gray wall within each divided group. The improvements in the calculation accuracies of radiative heat flux on the wall resulting from the new grouping strategy were evaluated using a series of 1D cases, in which combustion gases with strong inhomogeneities of temperature, pressure and molar ratio of water vapor to carbon dioxide were bounded by non-gray walls. The non-gray walls are assumed to be different metal materials with various surface states and temperatures. Finally, evaluation of the wavenumber subinterval grouping strategy was presented based on calculation of thermal imaging for directional radiation transfer from hot supersonic exhaust plume to a metal plate.