Improved Spectral Absorption Coefficient Grouping Strategies in Radiation Heat Transfer Calculations for H₂O-CO₂-Soot Mixtures

In the present work, strategies for the grouping of the spectral absorption coefficients used in multiscale (MS) multigroup (MG) full-spectrum k-distribution models were improved by considering the effects of variations in both temperature and species molar ratio on the correlated-k characteristics of the spectra of H2O-CO2-soot mixtures. The improvements in the accuracy of predictions of radiation heat transfer characteristics resulting from these new grouping strategies were evaluated using a series of semi-one-dimensional (1D) cases with significant temperature, participating species molar ratio, and pressure inhomogeneities. Finally, evaluations of grouping strategies were presented on calculation of the full-spectrum thermal images of an actual aeroengine combustor.