Handling of Collimated Irradiation on a Plane-Parallel Participating Medium

2000 ◽  
Author(s):  
Christian Proulx ◽  
Daniel R. Rousse ◽  
Rodolphe Vaillon ◽  
Jean-François Sacadura
Keyword(s):  
Heat Flux ◽  
Monte Carlo ◽  
Monte Carlo Method ◽  
Radiative Heat ◽  
Radiative Heat Flux ◽  
Scattering Media ◽  
One Dimensional ◽  
Plane Parallel ◽  
Collimated Beam ◽  
Good Agreement

Abstract This article presents selected results of a study comparing two procedures for the treatment of collimated irradiation impinging on one boundary of a participating one-dimensional plane-parallel medium. These procedures are implemented in a CVFEM used to calculate the radiative heat flux and source. Both isotropically and anisotropically scattering media are considered. The results presented show that both procedures provide results in good agreement with those obtained using a Monte Carlo method, when the collimated beam impinges normally.

Line-by-Line Random-Number Database for Monte Carlo Simulations of Radiation in Combustion System

2018 ◽  
Vol 141 (2) ◽  
Author(s):  
Tao Ren ◽  
Michael F. Modest
Keyword(s):  
Heat Transfer ◽  
Monte Carlo ◽  
Monte Carlo Method ◽  
Radiative Heat ◽  
Random Number ◽  
Test Cases ◽  
Combustion System ◽  
Absorption Coefficients ◽  
One Dimensional ◽  
The Monte Carlo Method

With today's computational capabilities, it has become possible to conduct line-by-line (LBL) accurate radiative heat transfer calculations in spectrally highly nongray combustion systems using the Monte Carlo method. In these calculations, wavenumbers carried by photon bundles must be determined in a statistically meaningful way. The wavenumbers for the emitting photons are found from a database, which tabulates wavenumber–random number relations for each species. In order to cover most conditions found in industrial practices, a database tabulating these relations for CO2, H2O, CO, CH4, C2H4, and soot is constructed to determine emission wavenumbers and absorption coefficients for mixtures at temperatures up to 3000 K and total pressures up to 80 bar. The accuracy of the database is tested by reconstructing absorption coefficient spectra from the tabulated database. One-dimensional test cases are used to validate the database against analytical LBL solutions. Sample calculations are also conducted for a luminous flame and a gas turbine combustion burner. The database is available from the author's website upon request.

Strategies for the Reduction of Pattern Effects

1996 ◽  
Vol 429 ◽  
Author(s):  
A. Kerscih ◽  
T. Schafbauer ◽  
L. Deutschmann
Keyword(s):  
Mathematical Model ◽  
Heat Flux ◽  
Monte Carlo ◽  
Spatial Variation ◽  
Spectral Dependence ◽  
Radiative Heat ◽  
The Other ◽  
Radiative Heat Flux ◽  
Simple Mathematical Model ◽  
Radiation Model

AbstractThe pattern effects in hot processes arise from a spatial variation of the radiative heat flux imbalance between emission and absorption. There are two scenarios to reduce the pattern effect: a very reflective chamber facing the patterned side with an illumination from the backside or a controlled double sided illumination on the other hand. The paper demonstrates the mechanism of both scenarios with a simple mathematical model and discusses the limitations of the approaches. The results will be exemplified with the help of reactor scale simulations involving a detailed Monte Carlo radiation model featuring continuous spectral dependence.

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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