WSGG correlations based on HITEMP2010 for gas mixtures of H2O and CO2 in high total pressure conditions

This study presents weighted-sum-of-gray-gases (WSGG) model coefficients for mixtures of H2O and CO2 with fixed mole ratio of 2/1 for high total pressure conditions. The mole ratio represents typical products of stoichiometric combustion of methane in air, which has received significant attention for high pressure applications. The coefficients are based on HITEMP2010 database, and are valid for path-lengths ranging from 0.01 to 30 m, temperatures varying from 400 to 2500 K, and total pressures of 1.0, 2.0, 5.0, 10, 20, and 40 atm. As a first validation of the WSGG model, a comparison with benchmark line-by-line (LBL) total emittance is presented, showing accurate results. Total emittance is shown to have significant pressure dependence, which emphasizes the importance of generating WSGG coefficients fitted to high pressure emittance values. To better assess the model accuracy, calculations for radiative heat flux and volumetric source are performed for two one-dimensional test cases, considering nonisothermal, homogeneous and non-homogeneous conditions. Results show acceptable deviations from the LBL solution for the homogeneous case, with even lower deviations for the non-homogeneous case, as long as the ratio between the species is fixed at 2/1. The effect of pressure is also significant on both radiative heat flux and volumetric source, while its behavior shows that interpolation is a good alternative to obtain WSGG solutions for intermediate pressures.