Radiative Heat Transfer Using Isotropic Scaling Approximation: Application to Fibrous Medium

2004 ◽  
Author(s):  
Herve´ T. Kamdem Tagne ◽  
Dominique Doermann Baillis
Keyword(s):  
Heat Transfer ◽  
Radiative Heat ◽  
Radiative Transfer Equation ◽  
Scattering Problem ◽  
Anisotropic Scattering ◽  
Radiative Properties ◽  
Heat Transfer Analysis ◽  
Discrete Ordinate Method ◽  
Discrete Ordinate ◽  
Fibrous Medium

The applicability of the isotropic scaling approximation to heat transfer analysis in fibrous medium is discussed. The isotropic scaling model allows the transformation of an anisotropic scattering problem to an isotropic one. The scaled parameters are derived for general anisotropic scattering and for radiative properties dependent of the incidence direction such as for fibrous medium. The fibers are randomly oriented either in space or parallel to the boundaries of the medium. The radiative transfer equation is solved with the discrete ordinate method and comparisons between the exact and the isotropic scaling problems for several Gauss quadrature are studied.

Radiative Heat Transfer Using Isotropic Scaling Approximation: Application to Fibrous Medium

2005 ◽  
Vol 127 (10) ◽  
pp. 1115-1123 ◽  
Author(s):  
Hervé Thierry Kamdem Tagne ◽  
Dominique Doermann Baillis
Keyword(s):  
Heat Transfer ◽  
Exact Solution ◽  
Radiative Heat Transfer ◽  
Radiative Heat ◽  
Scattering Problem ◽  
Incident Radiation ◽  
Anisotropic Scattering ◽  
Radiative Properties ◽  
Heat Transfer Analysis ◽  
Fibrous Medium

The applicability of the isotropic scaling approximation to heat transfer analysis in fibrous medium is discussed. The isotropic scaling model allows the transformation of an anisotropic scattering problem to an isotropic one. The scaled parameters are derived for general anisotropic scattering and for radiative properties dependent of the incidence radiation. Three different isotropic scaling approaches are considered: Directional isotropic scaling, mean isotropic scaling, and P1 isotropic scaling; corresponding to isotropic scaling parameters function of incident radiation, arithmetic mean over all incident direction of radiative properties, and mean on weighted radiative properties, respectively. The discrete ordinate method is used to solve the radiative transfer equation through fibrous medium. The fibers in the medium are randomly oriented either in space or parallel to the boundaries. Numerical results presented for a pure radiation problem show good accuracy on radiative heat flux between the exact solution and solution obtained with both P1 and directional isotropic scaling while using mean isotropic scaling is unsuitable. Using isotropic scaling approximation to model radiative heat transfer is faster than the exact solution and required few quadratures to converge.

Reduced Models for Radiative Heat Transfer Analysis Through Anisotropic Fibrous Medium

2010 ◽  
Vol 132 (7) ◽  
Author(s):  
Hervé Thierry Tagne Kamdem ◽  
Dominique Doermann Baillis
Keyword(s):  
Heat Transfer ◽  
Radiative Heat Transfer ◽  
Phase Function ◽  
Radiative Heat ◽  
Radiative Properties ◽  
Heat Transfer Analysis ◽  
Reduced Models ◽  
Fibrous Medium ◽  
Scattering Phase ◽  
Scattering Phase Function

Reduced models for radiative heat transfer analysis through anisotropic medium are presented and evaluated. The models include two equivalent heat transfer models through isotropic medium using isotropic or Henyey–Greenstein scattering phase functions with arithmetic or weighted means radiative properties calculated over all incident direction and an anisotropic model with directional radiative properties coupled to an isotropic scattering phase function or directional anisotropically scattering phase function. The pertinence of the models is investigated by solving coupled conduction/radiation heat transfer through a slab of anisotropic fibrous medium with fiber randomly oriented in the plan parallel to the boundaries. Good agreements on heat fluxes and thermal conductivity are obtained for reduced anisotropic models and for reduced equivalent isotropic models with weighted mean radiative properties.

Transient Radiative Heat Transfer Analysis of Turbid Tissues Subjected to Short-Pulsed Irradiations

2011 ◽  
Vol 110-116 ◽  
pp. 2999-3006
Author(s):  
Kyunghan Kim ◽  
Jongsoo Kim
Keyword(s):  
Heat Transfer ◽  
Radiative Heat Transfer ◽  
Radiative Heat ◽  
Abrupt Change ◽  
Radiation Energy ◽  
Heat Transfer Analysis ◽  
Discrete Ordinate ◽  
Conduction Model ◽  
Time Regime ◽  
Short Time

Transient radiative heat transfer of turbid tissues with a focused short-pulsed laser is studied. To investigate radiation transfer phenomenon during ultra short time regime, transient radiative transfer equation is adopted and it is solved by TDOM (Transient Discrete Ordinate Method). The nonuniform grid system is considered to capture abrupt change of radiation energy absorption. The hyperbolic conduction model is considered to predict temperature increment of turbid tissues.

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