A Monte Carlo method to solve for radiative effective thermal conductivity for particle beds of various solid fractions and emissivities
| Autor: | Ilker Tari, Evan Johnson, Derek Baker |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
Radiation
010504 meteorology & atmospheric sciences Monte Carlo method Thermal conduction 01 natural sciences Atomic and Molecular Physics and Optics Computational physics Thermal conductivity Isotropic solid Radiative transfer Particle Spectroscopy Distributed ray tracing 0105 earth and related environmental sciences Dimensionless quantity |
| Zdroj: | Journal of Quantitative Spectroscopy and Radiative Transfer |
| ISSN: | 0022-4073 |
| DOI: | 10.1016/j.jqsrt.2020.107014 |
| Popis: | A method is described to find the effective thermal conductivity due to radiation (krad) for groups of particles at packed and less than packed states. Unlike most previous studies, the method does not rely on the assumption of a unit cell or absorption and scattering coefficients to derive krad. In this method, radiation is modeled with a 3D Monte Carlo ray tracing code, steady state particle temperatures are found with a particle-particle heat exchange simulation, and krad is found with a comparison to heat conduction in an isotropic solid of the same geometry. This leads to the dimensionless Exchange Factor (FE), allowing krad to be calculated at any temperature and particle radius. The key result is a model for FE over the entire range of emissivities from 0.3 to 1 and solid fractions from 0.25 to the fully packed state of 0.64. FE results are compared to previous models, with agreement shown in some cases but a large disagreement found for low solid fractions. The krad results are combined with the Zehner and Schlunder model for solid and fluid conduction, providing an equation for the full effective thermal conductivity. |
| Databáze: | OpenAIRE |
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