Multi-start iterative reconstruction of the radiative parameter distributions in participating media based on the transient radiative transfer equation

2015 ◽  
Vol 351 ◽  
pp. 75-84 ◽  
Author(s):  
Yaobin Qiao ◽  
Hong Qi ◽  
Qin Chen ◽  
Liming Ruan ◽  
Heping Tan
Keyword(s):  
Radiative Transfer ◽  
Iterative Reconstruction ◽  
Transfer Equation ◽  
Radiative Transfer Equation ◽  
Participating Media ◽  
Radiative Parameter ◽  
Parameter Distributions

Propagation of Ultra-Short-Pulse Radiation in Participating Media: A Laguerre-Galerkin Solution

2007 ◽  
Author(s):  
Tuba Okutucu ◽  
Yaman Yener
Keyword(s):  
Radiative Transfer ◽  
Transfer Equation ◽  
Radiative Transfer Equation ◽  
Transfer Problem ◽  
Short Pulse ◽  
Optical Tomography ◽  
Time Derivative ◽  
Product Analysis ◽  
Participating Media ◽  
Radiative Transfer Problem

Transient analysis of the radiative transfer problem in participating media has become essential due to the recent applications involving extremely small time scales. In classical radiation problems, the time derivative term in the radiative transfer equation has a negligible order of magnitude compared to the others. Lasers of pico- to femtosecond pulse durations are now being used to investigate the properties of scattering and absorbing media in such applications as, optical tomography, combustion product analysis, and remote sensing. For such applications, the time derivative in the radiative transfer equation can no longer be neglected. Numerous approaches such as, integral formulation, direct numerical approach, discrete ordinates method, Monte Carlo simulations, and Galerkin technique have been introduced for the solution of transient radiative transfer problems in participating media. In the present work, Laguerre-Galerkin solutions for both rectangular and Gaussian incident pulse profiles are presented.

Correlation of Measured and Computed Radiation Intensity Exiting a Packed Bed

1996 ◽  
Vol 118 (1) ◽  
pp. 94-102 ◽  
Author(s):  
P. D. Jones ◽  
D. G. McLeod ◽  
D. E. Dorai-Raj
Keyword(s):  
Radiative Transfer ◽  
Radiation Intensity ◽  
Transfer Equation ◽  
Scattering Theory ◽  
Radiative Transfer Equation ◽  
Packed Bed ◽  
Radiative Properties ◽  
Discrete Ordinates ◽  
Measured Intensity ◽  
Participating Media

The spectral and directional distribution of radiation intensity is measured, using a direct radiometric technique, at the exposed boundary of a packed bed of stainless steel spheres. The purpose of these measurements is to provide an experimental data base of radiation intensity with which to correlate intensity field solutions of the radiative transfer equation in participating media. The bed is considered to be one-dimensional, is optically thick, and has measured constant-temperature boundary conditions. Intensity exiting the bed is numerically simulated using a discrete ordinates solution to the radiative transfer equation, with combined mode radiation-conduction solution of the coupled energy conservation equation. Radiative properties for the bed are computed using the large size parameter correlated scattering theory derived by Kamiuto from the general theory of dependent scattering by Tien and others. The measured intensity results show good agreement with computed results in near-normal directions, though agreement in near-grazing directions is poor. This suggests that either radiative transfer near the boundaries of this medium might not be adequately represented by a continuous form of the radiative transfer equation, or that the properties derived from correlated scattering theory are insufficient. In either case, development of a more detailed radiation model for spherical packed beds appears warranted.

Sign in / Sign up

Export Citation Format

Share Document