Metallic foams: Radiative properties/comparison between different models

Loretz, M.; Coquard, R.; Baillis, Dominique; Maire, Éric

doi:10.1016/j.jqsrt.2007.05.007

Cited by 95 publications

(22 citation statements)

References 5 publications

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“…This has mainly been achieved for highly porous materials. [410][411][412][413] The thermal properties of nuclear graphite are also of technological concern and have been predicted directly from CT images. 414 …”

Section: Image Based Modelling Of Cellular/porous Materialsmentioning

confidence: 99%

Quantitative X-ray tomography

Maire¹,

Withers²

2013

International Materials Reviews

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601

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X-ray computer tomography (CT) is fast becoming an accepted tool within the materials science community for the acquisition of 3D images. Here the authors review the current state of the art as CT transforms from a qualitative diagnostic tool to a quantitative one. Our review considers first the image acquisition process, including the use of iterative reconstruction strategies suited to specific segmentation tasks and emerging methods that provide more insight (e.g. fast and high resolution imaging, crystallite (grain) imaging) than conventional attenuation based tomography. Methods and shortcomings of CT are examined for the quantification of 3D volumetric data to extract key topological parameters such as phase fractions, phase contiguity, and damage levels as well as density variations. As a non-destructive technique, CT is an ideal means of following structural development over time via time lapse sequences of 3D images (sometimes called 3D movies or 4D imaging). This includes information needed to optimise manufacturing processes, for example sintering or solidification, or to highlight the proclivity of specific degradation processes under service conditions, such as intergranular corrosion or fatigue crack growth. Besides the repeated application of static 3D image quantification to track such changes, digital volume correlation (DVC) and particle tracking (PT) methods are enabling the mapping of deformation in 3D over time. Finally the use of CT images is considered as the starting point for numerical modelling based on realistic microstructures, for example to predict flow through porous materials, the crystalline deformation of polycrystalline aggregates or the mechanical properties of composite materials.

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Section: Image Based Modelling Of Cellular/porous Materialsmentioning

confidence: 99%

Quantitative X-ray tomography

Maire¹,

Withers²

2013

International Materials Reviews

Self Cite

1,064

601

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“…Note that considering the radiative heat transfer in the full sample of the macroporous material, scattering effects will still be present due to the material interfaces where reflection and refraction occurs. Some authors [4,5,12,21] have characterized samples of porous media by a scattering coefficient and phase function.…”

Section: Radiative Heat Transfermentioning

confidence: 99%

“…The interest in understanding the radiative-conductive coupling in semitransparent porous media comes from the fact that various models have been developed for the separate determination of the effective radiative [12] and effective conductive [13] properties but their application in the coupled case is ambiguous. Superimposing the effect of radiation and conduction in order to obtain a solution to a coupled problem seems convenient but not necessarily accurate.…”

Section: Introductionmentioning

confidence: 99%

Numerical quantification of coupling effects for radiation-conduction heat transfer in participating macroporous media: Investigation of a model geometry

Perraudin

Haussener

2017

International Journal of Heat and Mass Transfer

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a b s t r a c tRadiative-conductive heat transfer in porous media is usually investigated by decoupling the heat transfer modes and solving the volume-averaged continuum equations using effective transport properties. However, both modes are naturally coupled and coupling effects might significantly affect the results. We aim at providing quantitative understanding of the coupling effects occurring in a model geometry. This is an important first step towards improving the accuracy of heat transfer predictions in engineering applications.We developed a numerical method using a structured mesh, cell centered finite volumes and Monte Carlo ray tracing techniques in order to simulate the 3-dimensional and unsteady coupled radiativeconductive heat transfer in semitransparent macroporous media. We have optimized the numerical method with regards to memory and computational requirements leading to optimal performance and allowing to perform a parameter variation study for various steady state cases.We conducted a parameter study considering different optical and thermal material properties and boundary conditions in order to quantify the coupling effect between conduction and radiation, and to demonstrate its dependencies. In terms of thermal properties, it was found that the ratio of bulk thermal conductivities is governing the coupling effect. A distinct peak at a given conductivity ratio was found. The influence of optical properties is discussed in details. It was found that a significant coupling effect exists, reaching up to 15% of the total thermal heat flux.The verified modeling framework in conjunction with our non-dimensionalization offers a tool to investigate the importance of radiation-conduction coupling in a quantitative manner. It is an important step towards understanding the detailed mechanisms of radiation and conduction coupling and provides engineering guidelines on the importance of these effects.

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“…The computation of e↵ective radiative properties (extinction, scattering coefficients and phase function) has been performed from structural parameters estimated by 3D image analysis [41]. Numerical estimations were also directly obtained from CAD or CMT images [42][43][44], using the Radiative Distribution Function Identification (RDFI) method [45].…”

Section: Introductionmentioning

confidence: 99%

Numerical study of effective heat conductivities of foams by coupled conduction and radiation

Vignoles

Ortona

2016

International Journal of Thermal Sciences

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E↵ective thermal conductivities (ETC) under vacuum were computed numerically on 3D blocks of open-cell foams either obtained by X-ray tomography or generated by Computer-Aided Design (CAD) with ideal geometries.For the first time a Monte-Carlo/Random Walk code accounting for the coupling of conduction in the solid phase and of radiation in the pore space has been used. The whole range of conduction/radiation ratio, parameterized by a Nusselt number, has been scanned; a law relating the ETC to this parameter has been obtained. In all cases the conductive and radiative contributions are additive. The slope of the radiative contribution to the ETC is found to display a distinct behavior, depending on whether radiation or conduction dominates. The low-temperature regime has an emissivity-dependent ETC slope, while the high-temperature regime does not.The critical ratio between both regimes is related to the ratio between cell and strut diameters. In all cases, it is found that the ETC anisotropy decreases with temperature. Closing some windows enhances conduction parallel to the closing walls and reduces radiation perpendicular to them. This e↵ect is shown to influence the ETC eigendirections in actual media.

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Metallic foams: Radiative properties/comparison between different models

Cited by 95 publications

References 5 publications

Quantitative X-ray tomography

Quantitative X-ray tomography

Numerical quantification of coupling effects for radiation-conduction heat transfer in participating macroporous media: Investigation of a model geometry

Numerical study of effective heat conductivities of foams by coupled conduction and radiation

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