Evaluation of Coefficients for the Weighted Sum of Gray Gases Model

Abstract

The weighted sum of gray gases model postulates that total emissivity and absorptivity may be represented by the sum of a gray gas emissivity weighted with a temperature dependent factor. The gray gas emissivity is expressed in terms of a temperature-independent absorption coefficient, absorbing gas partial pressure, and path length. The weighting factors are given by polynomials in gas temperature with associated polynomial coefficients. For absorptivity, a second polynomial for the irradiation temperature is introduced. A regression scheme is employed to fit the model to total emissivity and absorptivity values obtained from the exponential wide-band model. Absorption and polynomial coefficients are reported for carbon dioxide, water vapor, and mixtures of these gases. The model with these coefficients more accurately represents the total properties over a wider range of temperatures and partial pressure-path length products than previously available coefficients.

Analysis of Coal Combustion and Particle Temperature Profiles in a Rotary Kiln for Production of Light-weight Aggregate

“…벽면, 가스 및 입자의 복사열전달은 구 분종좌법(discrete ordinate method)을 적용하였다. 이 때 CO2와 H2O를 포함한 가스의 흡수계수는 회색기 체가중합법(weighted sum of the gray gases model, WSGGM) [8,9]을 이용하여 계산하였다. …”

Simulación Numérica del Efecto de un Mecanismo de Estratificación de Aire en un Quemador de Alta Velocidad

“…Debido a la influencia del vapor de agua y el CO2 sobre los patrones de radiación, se hizo necesaria la incorporación del modelo de suma ponderada de gases Grises (Smith et al, 1982;Coppalle & Vervisch, 1983;Denison & Webb, 1993).…”

Effect of Air-Fuel Ratio on Temperature Distribution and Pollutants for Biogas Mild Combustion

“…In this work, the RANS equations together with the realizable k-ε turbulence model [36] were solved, as used previously for MILD combustion [37]. The discrete ordinate radiation model [38] and absorption coefficient of weighted sum of gray gas (WSGGM) model were used [39,40]. The discrete ordinates radiation model solves the radiative transfer equation for a finite number of discrete solid angles in Cartesian system.…”