Explicit formulation of a nodal transport method for discrete ordinates calculations in two-dimensional fixed-source problems

Kerntechnik ◽  
2014 ◽  
Vol 79 (2) ◽  
pp. 155-162 ◽  
Author(s):  
A. Tres ◽  
C. B. Picoloto ◽  
J. F. Prolo Filho ◽  
R. D. da Cunha ◽  
L. B. Barichello
Keyword(s):  
Discrete Ordinates ◽  
Two Dimensional ◽  
Explicit Formulation ◽  
Nodal Transport ◽  
Transport Method

Two-dimensional nodal transport method for triangular geometry

2007 ◽  
Vol 34 (5) ◽  
pp. 424-432 ◽  
Author(s):  
Haoliang Lu ◽  
Hongchun Wu ◽  
Liangzhi Cao ◽  
Yongqiang Zhou ◽  
Chunyu Xian ◽  
...  
Keyword(s):  
Two Dimensional ◽  
Nodal Transport ◽  
Transport Method

Numerical Modeling of Radiative and Reactive Flow Field Around a Blunt Body at Hypersonic Regimes

2010 ◽  
Author(s):  
Morteza Rahmanpour ◽  
Reza Ebrahimi ◽  
Mehrzad Shams
Keyword(s):  
Flow Field ◽  
Differential Equations ◽  
Heat Fluxes ◽  
Transitional Flow ◽  
Navier Stokes ◽  
Implicit Time ◽  
Discrete Ordinates ◽  
Two Dimensional ◽  
Fully Implicit ◽  
Time Marching

A numerical method for calculation of strong radiation for two-dimensional reactive air flow field is developed. The governing equations are taken to be two dimensional, compressible Reynolds-average Navier-Stokes and species transport equations. Also, radiation heat flux in energy equation is evaluated using a model of discrete ordinate method. The model used S4 approximation to reduce the governing system of integro-differential equations to coupled set of partial differential equations. A multiband model is used to construct absorption coefficients. Tangent slab approximation is assumed to determine the characteristic parameters needed in the Discrete Ordinates Method. The turbulent diffusion and heat fluxes are modeled by Baldwin and Lomax method. The flow solution is obtained with a fully implicit time marching method. A thermochemical nonequilibrium formulation appropriate to hypersonic transitional flow of air is presented. The method is compared with existing experimental results and good agreement is observed.

Comparison of three discrete ordinates methods applied to two-dimensional curved geometries

2003 ◽  
Vol 42 (4) ◽  
pp. 343-359 ◽  
Author(s):  
Hong-Mo Koo ◽  
Rodolphe Vaillon ◽  
Vincent Goutière ◽  
Vital Le Dez ◽  
Hojin Cha ◽  
...  
Keyword(s):  
Discrete Ordinates ◽  
Two Dimensional

Two-Dimensional Discrete Ordinates Photon Transport Calculations for Brachytherapy Dosimetry Applications

2000 ◽  
Vol 134 (2) ◽  
pp. 121-134 ◽  
Author(s):  
George M. Daskalov ◽  
Randal S. Baker ◽  
Robert C. Little ◽  
David W. O. Rogers ◽  
Jeffrey F. Williamson
Keyword(s):  
Discrete Ordinates ◽  
Two Dimensional ◽  
Photon Transport

Simulations of Thermal Performance for One- and Two-Dimensional Insulation and Aluminum Foil Fire Barriers

2004 ◽  
Author(s):  
Mauricio A. Sa´nchez ◽  
William H. Sutton ◽  
Carlos A. Sa´nchez
Keyword(s):  
Heat Transfer ◽  
Numerical Model ◽  
Thermal Performance ◽  
Structural Integrity ◽  
High Energy ◽  
Ceramic Fiber ◽  
Discrete Ordinates ◽  
Two Dimensional ◽  
Barrier Materials ◽  
Fire Barrier

Nonbearing walls made of concrete frequently include one or two-dimensional gaps between sections to allow the concrete exert expansion or contraction due to temperature transients. These section gaps require the use of a thermal fire barrier to stop a fire from spreading during a period of time. In some applications, such as seismic structures, fire barriers are large and form substructures and partial enclosures. These type of fire barriers are often manufactured by layering alternating blankets of ceramic fiber insulation with bounding thin metallic foil sheets. In this case, the barrier must meet the specifications and effectiveness given by the ASTM standard E-119. This effectiveness is determined by the requirement of maintaining structural integrity by allowing some heat release while not permitting the fire flame to pass through. Little data is available on the thermal interaction of 2-D corners and splicing the layers for large barriers. It is expected that spatial and angular effects might either degrade performance or even cause “hot spots” in a barrier wall. Therefore, a numerical simulation of the barrier is accomplished by utilizing the spectral/gray and directional/modeled data of each one of the components and by taking into account two common geometrical building shapes. This simulation analysis is done by coupling of the discrete ordinates method in radiation heat transfer and the energy equation to previously published thermophysical experimental data used as a validation of the properties for fire barrier materials. Some of the effects of directional and surface properties and radiative heat transfer in fire barrier materials have been included in the numerical model. The Fluent®-based numerical model is able to match thermal performance of previous test systems. Initial calculations suggest that a fire barrier consisting of a 2D corner geometry exposed to a fire from either side would be thermally less robust than a slab of the same characteristic aspect ratio. This approximation has shown a preferential orientation for the barrier to be positioned when a fire or other high energy source is postulated.

Analysis of Heterogeneous Cores Using SN Code With Discontinuity Factor

2014 ◽  
Author(s):  
Jing Zhao ◽  
Zhihong Liu ◽  
Chunlin Wei ◽  
Yongming Hu
Keyword(s):  
Common Method ◽  
Diffusion Equations ◽  
Homogenization Theory ◽  
Discrete Ordinates ◽  
The Common ◽  
Transport Method ◽  
Diffusion Computation ◽  
Heterogeneous Cores

Solving diffusion equations with the equivalence homogenization theory is the common method in reactor neutronics. But for some case, as for stronger absorbers, the diffusion equations will bring great errors and the transport method will be more suitable. The discontinuity factor theory has been successfully used in core diffusion computation programs and effectively reduced the homogenization error. The method of using the discontinuity factor in the transport method were studied. The result shows that higher accuracy was obtained from the discrete ordinates core transport computation program with discontinued factor.

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