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.

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 Non-grey gas radiative transfer analyses using the statistical narrow-band model

1998 ◽  
Vol 41 (14) ◽  
pp. 2227-2236 ◽  
Author(s):  
F. Liu ◽  
Ö.L. Gülder ◽  
G.J. Smallwood ◽  
Y. Ju
Keyword(s):  
Radiative Transfer ◽  
Narrow Band ◽  
Band Model ◽  
Narrow Band Model

scholarly journals Numerical Solutions of Three-Dimensional Non-Grey Gas Radiative Transfer Using the Statistical Narrow-Band Model

1999 ◽  
Vol 121 (1) ◽  
pp. 200-203 ◽  
Author(s):  
F. Liu
Keyword(s):  
Radiative Transfer ◽  
Numerical Solutions ◽  
Radiative Transfer Equation ◽  
Narrow Band ◽  
Pure Water ◽  
Three Dimensional ◽  
Band Model ◽  
Real Gas ◽  
Gas Radiation ◽  
Narrow Band Model

Three-dimensional non-grey gas radiation analyses were conducted using the statistical narrow-band model along with up-dated band parameters. The exact narrow-band averaged radiative transfer equation was solved using a ray-tracing method. Accurate numerical results were presented for non-grey real gas radiative transfer in a three-dimensional rectangular enclosure containing (i) an isothermal pure water vapor at 1000 K and 1 atm, (ii) an isothermal and inhomogeneous H2O/N2 mixture at 1000 K and 1 atm, and (iii) a nonisothermal and homogeneous mixture of CO2/H2O/N2 at 1 atm.

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.

Monte Carlo Simulation of Radiation in Gases With a Narrow-Band Model and a Net-Exchange Formulation

1996 ◽  
Vol 118 (2) ◽  
pp. 401-407 ◽  
Author(s):  
M. Cherkaoui ◽  
J.-L. Dufresne ◽  
R. Fournier ◽  
J.-Y. Grandpeix ◽  
A. Lahellec
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Method ◽  
Radiative Heat ◽  
Computation Time ◽  
Band Model ◽  
One Dimensional ◽  
The Monte Carlo Method ◽  
Reflecting Surfaces ◽  
Heat Transfers ◽  
Narrow Band Model

The Monte Carlo method is used for simulation of radiative heat transfers in nongray gases. The proposed procedure is based on a Net-Exchange Formulation (NEF). Such a formulation provides an efficient way of systematically fulfilling the reciprocity principle, which avoids some of the major problems usually associated with the Monte Carlo method: Numerical efficiency becomes independent of optical thickness, strongly nonuniform grid sizes can be used with no increase in computation time, and configurations with small temperature differences can be addressed with very good accuracy. The Exchange Monte Carlo Method (EMCM) is detailed for a one-dimensional slab with diffusely or specularly reflecting surfaces.

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