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.

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.

Prediction of Radiative Heat Transfer in Industrial Equipment Using the Radiation Element Method

2001 ◽  
Vol 123 (4) ◽  
pp. 530-536 ◽  
Author(s):  
Zhixiong Guo ◽  
Shigenao Maruyama
Keyword(s):  
Heat Transfer ◽  
Radiative Heat Transfer ◽  
Radiative Heat ◽  
Narrow Band ◽  
Particle Density ◽  
Three Dimensional ◽  
Wide Band ◽  
Band Model ◽  
Participating Media ◽  
Carbon Particles

The radiation element method by ray emission method, REM2, has been formulated to predict radiative heat transfer in three-dimensional arbitrary participating media with nongray and anisotropically scattering properties surrounded by opaque surfaces. To validate the method, benchmark comparisons were conducted against the existing several radiation methods in a rectangular three-dimensional media composed of a gas mixture of carbon dioxide and nitrogen and suspended carbon particles. Good agreements between the present method and the Monte Carlo method were found with several particle density variations, in which participating media of optical thin, medium, and thick were included. As a numerical example, the present method is applied to predict radiative heat transfer in a boiler model with nonisothermal combustion gas and carbon particles and diffuse surface wall. Elsasser narrow-band model as well as exponential wide-band model is adopted to consider the spectral character of CO2 and H2O gases. The distributions of heat flux and heat flux divergence in the boiler furnace are obtained. The difference of results between narrow-band and wide-band models is discussed. The effects of gas model, particle density, and anisotropic scattering are scrutinized.

Investigation of Radiative Transfer in Nongray Gases Using a Narrow Band Model and Monte Carlo Simulation

1994 ◽  
Vol 116 (1) ◽  
pp. 160-166 ◽  
Author(s):  
J. Liu ◽  
S. N. Tiwari
Keyword(s):  
Monte Carlo ◽  
Radiative Transfer ◽  
Narrow Band ◽  
Heat Fluxes ◽  
Radiative Energy ◽  
Band Model ◽  
Spectral Correlation ◽  
The Monte Carlo Method ◽  
Finite Volume Element ◽  
Narrow Band Model

The Monte Carlo method (MCM) is applied to analyze radiative heat transfer in nongray gases. The nongray model employed is based on the statistical narrow band model with an exponential-tailed inverse intensity distribution. The amount and transfer of the emitted radiative energy in a finite volume element within a medium are considered in an exact manner. The spectral correlation between transmittances of two different segments of the same path in a medium makes the statistical relationship different from the conventional relationship that only provides the noncorrelated results for nongray analysis. Two features of the MCM that are different from other nongray numerical methods are discussed. The simplicity of the MCM is demonstrated by considering the case of radiative transfer between two reflecting walls. The results for the radiative dissipation distributions and the net radiative wall heat fluxes are obtained for uniform, parabolic, and boundary layer type temperature profiles, as well as for a parabolic concentration profile. They are compared with available results of other methods. Good agreements are found for all the cases considered.

Discrete Ordinates Solutions of Nongray Radiative Transfer With Diffusely Reflecting Walls

1993 ◽  
Vol 115 (1) ◽  
pp. 184-193 ◽  
Author(s):  
J. A. Menart ◽  
HaeOk Skarda Lee ◽  
Tae-Kuk Kim
Keyword(s):  
Radiative Transfer ◽  
Numerical Solutions ◽  
Correlation Effect ◽  
Heat Fluxes ◽  
Discrete Ordinates ◽  
Band Model ◽  
Multiple Reflections ◽  
Spectral Correlation ◽  
Closure Approximation ◽  
Spectral Equation

Nongray gas radiation in a plane parallel slab bounded by gray, diffusely reflecting walls is studied using the discrete ordinates method. The spectral equation of transfer is averaged over a narrow wavenumber interval preserving the spectral correlation effect. The governing equations are derived by considering the history of multiple reflections between two reflecting walls. A closure approximation is applied so that only a finite number of reflections have to be explicitly included. The closure solutions express the physics of the problem to a very high degree and show relatively little error. Numerical solutions are obtained by applying a statistical narrow-band model for gas properties and a discrete ordinates code. The net radiative wall heat fluxes and the radiative source distributions are obtained for different temperature profiles. A zeroth-degree formulation, where no wall reflection is handled explicitly, is sufficient to predict the radiative transfer accurately for most cases considered, when compared with increasingly accurate solutions based on explicitly tracing a larger number of wall reflections without any closure approximation applied.

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.

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