Eventos Anais de eventos
COBEM 2019
25th International Congress of Mechanical Engineering
Evaluation of Different Weighted-Sum-of-Gray-Gases Formulations to Estimate the Planck-Mean Absorption Coefficient for CO2-H2O Mixtures
Submission Author:
Guilherme Crivelli Fraga , SP
Co-Authors:
Guilherme Crivelli Fraga, Francis França, Pedro Coelho
Presenter: Guilherme Crivelli Fraga
doi://10.26678/ABCM.COBEM2019.COB2019-1297
Abstract
A methodology for calculating the Planck-mean absorption coefficient κP of a participating medium composed by carbon dioxide and water vapor using the underlying hypotheses and correlations of the weighted-sum-of-gray-gases (WSGG) model is presented. Different WSGG formulations are tested and compared to the values of κP obtained by line-by-line integration of a high-resolution spectral database and by existing correlations directly developed for computing that coefficient. Mixtures representative of three different scenarios are considered: atmospheric air-fuel combustion, atmospheric oxy-fuel combustion and high-pressure conditions. The results show that the WSGG model is capable of very good predictions of κP for intermediate-to-high temperatures, even outperforming some of the existing correlations for the Planck-mean absorption coefficient. However, when applied to the actual solution of radiative transfer problems using the gray-gas assumption, this methodology leads to greater errors than adopting Bouguer’s law for evaluating the gray-gas absorption coefficient.
Keywords
radiative transfer, Planck-mean absorption coefficient, weighted-sum-of-gray-gases model, air-fuel combustion, oxy-fuel combustion
