scholarly journals ON INCREASING THE EFFICIENCY OF A DISCRETE ORDINATES RADIATIVE TRANSFER METHOD WITH PERIODIC RELATIONS

2005 ◽  
Vol 4 (2) ◽  
pp. 181
Author(s):  
M. P. De Abreu
Keyword(s):  
Radiative Transfer ◽  
Computer Time ◽  
Anisotropic Scattering ◽  
Discrete Ordinates ◽  
Coupling Coefficients ◽  
Radiation Beam ◽  
Component Method ◽  
Two Component ◽  
Transfer Method ◽  
Transfer Problems

In this article, improvements in a recently developed discrete ordinates method – the two-component method - are reported. The method solves conservative and non-conservative radiative heat transfer problems with anisotropic scattering on a multislab domain irradiated from one side with a radiation beam. The beam here consists of a monodirectional (singular) stream and of a continuous (regular) distribution in angle. Specifically, the computational efficiency of this two-component method has been increased with the help of new periodic relations for the coupling coefficients that appear in the numerical component of the method. With these periodic relations, memory usage requirement for storing the (usually large number of) coupling coefficients has been halved, while saving computer time from unnecessary computation of redundant coefficients. The increased efficiency of the two-component method has been illustrated with numerical results and discussion of a model problem in shortwave radiative transfer.

scholarly journals ON INCREASING THE EFFICIENCY OF A DISCRETE ORDINATES RADIATIVE TRANSFER METHOD WITH PERIODIC RELATIONS

2005 ◽  
Vol 4 (2) ◽  
Author(s):  
M. P. De Abreu
Keyword(s):  
Radiative Transfer ◽  
Computer Time ◽  
Anisotropic Scattering ◽  
Discrete Ordinates ◽  
Coupling Coefficients ◽  
Radiation Beam ◽  
Component Method ◽  
Two Component ◽  
Transfer Method ◽  
Transfer Problems

In this article, improvements in a recently developed discrete ordinates method – the two-component method - are reported. The method solves conservative and non-conservative radiative heat transfer problems with anisotropic scattering on a multislab domain irradiated from one side with a radiation beam. The beam here consists of a monodirectional (singular) stream and of a continuous (regular) distribution in angle. Specifically, the computational efficiency of this two-component method has been increased with the help of new periodic relations for the coupling coefficients that appear in the numerical component of the method. With these periodic relations, memory usage requirement for storing the (usually large number of) coupling coefficients has been halved, while saving computer time from unnecessary computation of redundant coefficients. The increased efficiency of the two-component method has been illustrated with numerical results and discussion of a model problem in shortwave radiative transfer.

DISCRETE TRANSFER METHOD APPLIED TO TRANSIENT RADIATIVE TRANSFER PROBLEMS IN PARTICIPATING MEDIUM

2003 ◽  
Vol 44 (2) ◽  
pp. 183-197 ◽  
Author(s):  
P. Rath ◽  
S. C. Mishra ◽  
P. Mahanta ◽  
U. K. Saha ◽  
K. Mitra
Keyword(s):  
Radiative Transfer ◽  
Transfer Method ◽  
Transfer Problems

Implementation of SLW model in the radiative heat transfer problems with particles and high temperature gradients

2017 ◽  
Vol 27 (5) ◽  
pp. 1128-1141 ◽  
Author(s):  
Rahul Yadav ◽  
C. Balaji ◽  
S.P. Venkateshan
Keyword(s):  
High Temperature ◽  
Radiative Heat ◽  
Anisotropic Scattering ◽  
Heat Fluxes ◽  
Temperature Gradients ◽  
Discrete Ordinates ◽  
Content Type ◽  
Practical Applications ◽  
Transfer Problems ◽  
Rocket Exhaust

Purpose The paper aims to test the spectral line-based weighted sum of gray gases (SLW) method in axisymmetric geometries with particles and high temperature gradients. Design/methodology/approach An SLW model is coupled with Trivic’s mean wavelength approach to estimate the radiative heat fluxes at the wall of an enclosure and to the base wall of the rocket exhaust, thereby subsequently studying the effect of concentration variation of the gases and particles in these cases. Radiative transfer equation is solved using modified discrete ordinates method. Anisotropic scattering is modeled using transport approximation. Findings Two cases considered show the importance of particle emission and scattering in the rocket plume base heating problems. In cases involving only gases, the concentration of H2O tends to have more impact on the flux values than any other gas. Originality/value A full model of gases with particles in an axially varying temperature field is reported. Such cases are very common in practical applications. The present methodology gives more insight and a firm handle on the problem vis-a-vis other traditional techniques.

Least-Squares Finite Element Analysis for Transient Radiative Transfer in Absorbing and Scattering Media

2005 ◽  
Vol 128 (5) ◽  
pp. 499-503 ◽  
Author(s):  
W. An ◽  
L. M. Ruan ◽  
H. P. Tan ◽  
H. Qi
Keyword(s):  
Finite Element ◽  
Radiative Transfer ◽  
Least Squares ◽  
Present Model ◽  
Element Model ◽  
Discrete Ordinates ◽  
Scattering Media ◽  
Element Analysis ◽  
Volume Method ◽  
Transfer Problems

In some radiative transfer processes, the time scales are usually on the order of 10−9-10−15s, so the transient effect of radiation should be considered. In present research, a finite element model, which is based on the discrete ordinates method and least-squares variational principle, is developed to simulate the transient radiative transfer in absorbing and scattering media. The numerical formulations and detailed steps are given. Moreover, two transient radiative transfer problems are investigated and the results are compared with those by integral method and finite volume method. It indicates that the present model can simulate the transient radiative transfer effectively and accurately.

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