Evaluation of coefficients for the weighted sum of gray gases model
Abstract
The weighted sum of gray gases model postulates that the total emissivity and absorptivity may be represented to any desired degree of accuracy by the sum of a gray gas emissivity (or absorptivity) weighted with a temperature dependent factor. The gray gas emissivity is expressed in terms of an absorption coefficient and product of the absorbing gas partial pressure and path length. The weighting factors are generally given by polynomials in gas temperature with associated polynomial coefficients. For absorptivity, a second polynomial for the surface irradiation temperature must be introduced. Absorption and polynomial coefficients are reported for total emissivity and absorptivity for carbon dioxide, water vapor, and mixtures of these gases. A regression scheme was employed to fit the model to property values of total emissivity and absorptivity obtained from the exponential wide band model.
 Publication:

ASME and American Institute of Chemical Engineers, 20th National Heat Transfer Conference
 Pub Date:
 August 1981
 Bibcode:
 1981ceht.confQ....S
 Keywords:

 Absorptivity;
 Coefficients;
 Emissivity;
 Gray Gas;
 Mathematical Models;
 Weighting Functions;
 Carbon Dioxide;
 Gas Mixtures;
 Gas Temperature;
 Polynomials;
 Regression Analysis;
 Sums;
 Temperature Dependence;
 Water;
 Fluid Mechanics and Heat Transfer