MODELING OF THE ABSORPTION COEFFICIENT IN THE EXPONENTIAL WIDE BAND MODEL (EWBM)

2004 ◽  
Author(s):  
Bengt Sunden ◽  
M. Bahador
Keyword(s):  
Absorption Coefficient ◽  
Wide Band ◽  
Band Model ◽  
Wide Band Model

Thermal Radiation Properties of Acetylene

1985 ◽  
Vol 107 (4) ◽  
pp. 943-948 ◽  
Author(s):  
M. A. Brosmer ◽  
C. L. Tien
Keyword(s):  
Absorption Coefficient ◽  
Thermal Radiation ◽  
Narrow Band ◽  
Wide Band ◽  
Band Model ◽  
Radiation Properties ◽  
Wide Band Model ◽  
Combination Bands ◽  
Total Emissivity

The spectral absorptivities of the ν3 and ν5 fundamental and the ν4 + ν5 combination bands of acetylene have been measured at low resolution for temperatures between 290 and 600 K. These measurements allow the determination of spectral-mean (narrow-band) parameters for the three bands based on the Elsasser and Goody models and the correlation of the band absorptance data using the Edwards exponential wide-band model. Charts for the total emissivity and Planck mean absorption coefficient have been developed for acetylene based on the wide-band parameters.

scholarly journals Influence of the Spectral Model of Radiation on the Calculated Characteristics of Complex Heat Exchange in Flame Furnaces of the Petrochemical Industry

2020 ◽  
Vol 6 (6) ◽  
pp. 42-47
Author(s):  
A. Abdullin
Keyword(s):  
Petrochemical Industry ◽  
Wide Band ◽  
Combustion Products ◽  
Heat Fluxes ◽  
Spectral Model ◽  
Band Model ◽  
Total Heat Transfer ◽  
Complex Heat Exchange ◽  
Tube Furnaces ◽  
Wide Band Model

The influence of the spectral model of radiation on heat fluxes and the temperature of combustion products in the radiant chambers of tube furnaces of the petrochemical industry is analyzed. A wide-band model and a Hottel gray model are considered. It is shown that the spectral model of the combustion medium radiation weakly affects the calculated characteristics of the total heat transfer.

Nongray Radiative Gas Analyses Using the S-N Discrete Ordinates Method

1991 ◽  
Vol 113 (4) ◽  
pp. 946-952 ◽  
Author(s):  
T. K. Kim ◽  
J. A. Menart ◽  
H. S. Lee
Keyword(s):  
Radiative Heat ◽  
Narrow Band ◽  
Wide Band ◽  
Heat Fluxes ◽  
Discrete Ordinates ◽  
Band Model ◽  
Spectral Correlation ◽  
Discrete Ordinates Method ◽  
Computational Speed ◽  
Wide Band Model

The S-N discrete ordinates method is applied to analyze radiative heat transfer in nongray gases. Spectral correlation between the terms in the equation of transfer is considered for black or nearly nonreflecting walls. Formulations to apply the S-N method using a narrow-band or the exponential wide-band model are presented. The net radiative wall heat fluxes and the radiative source distributions are obtained for uniform, parabolic, and boundary layer type temperature profiles, as well as for a parabolic concentration profile. The narrow- and wide-band nongray solutions are compared with gray-band approximations using the same band models. The computational speed of the gray-band approximation is obtained at the expense of accuracy in the internal fluxes and radiative source distributions. The wall radiative flux predictions by the gray-band approximation are satisfactory.

Evaluation of Coefficients for the Weighted Sum of Gray Gases Model

1982 ◽  
Vol 104 (4) ◽  
pp. 602-608 ◽  
Author(s):  
T. F. Smith ◽  
Z. F. Shen ◽  
J. N. Friedman
Keyword(s):  
Partial Pressure ◽  
Path Length ◽  
Wide Band ◽  
Band Model ◽  
Weighted Sum ◽  
Gas Temperature ◽  
Temperature Dependent ◽  
Polynomial Coefficients ◽  
Wide Band Model ◽  
Total Emissivity

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.

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