Simulation of Focused Radiation Propagation and Transient Heat Transfer in Turbid Tissues

2009 ◽  
Author(s):  
Jian Jiao ◽  
Zhixiong Guo
Keyword(s):  
Heat Transfer ◽  
Thermal Analysis ◽  
Pulse Train ◽  
Radiation Transport ◽  
Time Dependent ◽  
Transfer Model ◽  
Discrete Ordinate Method ◽  
Discrete Ordinate ◽  
Physiological Properties ◽  
Focused Beam

Thermal analysis of a cylindrical tissue subject to a train of ultrashort pulse irradiations was made by developing a combined time-dependent radiation and conduction bio-heat transfer model. Ultrashort pulsed radiation transport in the cylindrical tissue is simulated using the transient discrete ordinate method. Treatment of focused beam is introduced. The model skin tissue is stratified as three layers with different optical, thermal and physiological properties. Comparisons between the collimated irradiation and focused beam are conducted. The effect of pulse train is investigated.

scholarly journals Optimization and parallelization of the discrete ordinate method for radiation transport simulation in OpenFOAM: Hierarchical combination of shared and distributed memory approaches

2021 ◽  
Vol 1 ◽  
pp. 2
Author(s):  
Jose Moreno-SanSegundo ◽  
Cintia Casado ◽  
David Concha ◽  
Antonio S. Montemayor ◽  
Javier Marugán
Keyword(s):  
Distributed Memory ◽  
Radiation Transport ◽  
Computational Time ◽  
Limiting Factor ◽  
Discrete Ordinate Method ◽  
Discrete Ordinate ◽  
Radiation Sources ◽  
Transport Problems ◽  
Volume Models ◽  
Spatial Cell

This paper describes the reduction in memory and computational time for the simulation of complex radiation transport problems with the discrete ordinate method (DOM) model in the open-source computational fluid dynamics platform OpenFOAM. Finite volume models require storage of vector variables in each spatial cell; DOM introduces two additional discretizations, in direction and wavelength, making memory a limiting factor. Using specific classes for radiation sources data, changing the store of fluxes and other minor changes allowed a reduction of 75% in memory requirements. Besides, a hierarchical parallelization was developed, where each node of the standard parallelization uses several computing threads, allowing higher speed and scalability of the problem. This architecture, combined with optimization of some parts of the code, allowed a global speedup of x15. This relevant reduction in time and memory of radiation transport opens a new horizon of applications previously unaffordable.

scholarly journals An Efficient Implementation of the Finite-volume Method For the Solution of Radiation Transport in Circuit Breakers

2017 ◽  
Vol 4 (2) ◽  
pp. 177-181
Author(s):  
A. Mazaheri ◽  
J. Y. Trépanier ◽  
R. Camarero ◽  
P. Robin-Jouan
Keyword(s):  
Finite Volume ◽  
Radiation Transport ◽  
Computation Time ◽  
Discrete Ordinate Method ◽  
Discrete Ordinate ◽  
Circuit Breakers ◽  
Explicit Approach ◽  
Order Of Magnitude ◽  
Implicit Approach ◽  
Volume Method

In this paper, we propose to revisit the method to solve the radiation transport equation in circuit breakers to reduce the computation time. It is based on an explicit approach using a space marching algorithm. The method can further be accelerated using a Cartesian grid and using the axisymmetric assumption. Comparisons performed in terms of accuracy and efficiency between the P1 model, the implicit finite-volume discrete ordinate method and the space-marching finite-volume discrete ordinate method show that the explicit approach is more that an order of magnitude faster than the implicit approach, for the same accuracy.

SHDOMPPDA: A Radiative Transfer Model for Cloudy Sky Data Assimilation

2007 ◽  
Vol 64 (11) ◽  
pp. 3854-3864 ◽  
Author(s):  
K. Franklin Evans
Keyword(s):  
Radiative Transfer ◽  
Data Assimilation ◽  
Spherical Harmonics ◽  
Forward Model ◽  
Radiative Transfer Model ◽  
Computational Time ◽  
Transfer Model ◽  
Discrete Ordinate Method ◽  
Discrete Ordinate ◽  
Plane Parallel

Abstract The spherical harmonics discrete ordinate method for plane-parallel data assimilation (SHDOMPPDA) model is an unpolarized plane-parallel radiative transfer forward model, with corresponding tangent linear and adjoint models, suitable for use in assimilating cloudy sky visible and infrared radiances. It is derived from the spherical harmonics discrete ordinate method plane-parallel (SHDOMPP, also described in this article) version of the spherical harmonics discrete ordinate method (SHDOM) model for three-dimensional atmospheric radiative transfer. The inputs to the SHDOMPPDA forward model are profiles of pressure, temperature, water vapor, and mass mixing ratio and number concentration for a number of hydrometeor species. Hydrometeor optical properties, including detailed phase functions, are determined from lookup tables as a function of mass mean radius. The SHDOMPP and SHDOMPPDA algorithms and construction of the tangent-linear and adjoint models are described. The SHDOMPPDA forward model is validated against the Discrete Ordinate Radiative Transfer Model (DISORT) by comparing upwelling radiances in multiple directions from 100 cloud model columns at visible and midinfrared wavelengths. For this test in optically thick clouds the computational time for SHDOMPPDA is comparable to DISORT for visible reflection, and roughly 5 times faster for thermal emission. The tangent linear and adjoint models are validated by comparison to finite differencing of the forward model.

Two-Phase Flow Heat and Mass Transfer Model Construction and Experiment Study of the Fuel Evaporation Progress

2012 ◽  
Vol 614-615 ◽  
pp. 174-180
Author(s):  
Bo Yun Liu ◽  
Jin Yun Pu ◽  
Xiang Lie Yi
Keyword(s):  
Heat Transfer ◽  
Mass Transfer ◽  
Two Phase Flow ◽  
Time Dependent ◽  
Transfer Model ◽  
Phase Flow ◽  
Two Phase ◽  
Dependent Behavior ◽  
Mass Evaporation ◽  
Hot Surface

As for the time-dependent behavior of the fuel heat and mass evaporation transfer progress on hot surface,consider the convective mass transfer and heat transfer, the liquid-gas two-phase flow of continuous heat transfer model was studied. By the dimensionless transform, the time-dependent behavior of the concentration distribution and the temperature field was obtained. The result of n-Heptanes evaporation transfer progress on hot surface experiment is consistent with the academic model.

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