Experimental investigations of the coupled conductive and radiative heat transfer in metallic/ceramic foams

Coquard, R.; Rochais, Denis; Baillis, Dominique

doi:10.1016/j.ijheatmasstransfer.2009.05.015

Cited by 88 publications

(40 citation statements)

References 27 publications

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“…In Eqs. (2) and (3) the wavelength dependency has been dropped, since grey media and surroundings are considered in this study. The relevant properties for an emitting, absorbing and scattering medium are the absorption, j, and scattering, r s , coefficients and the scattering phase function, U.…”

Section: Radiative Heat Transfermentioning

confidence: 99%

“…Details of volume averaging theory applied to problems relevant in heat and mass transfer are described in [1]. Effective properties can be determined experimentally [2,3] or through simulations. As the effective properties significantly depend on the geometry of the porous media, accurate computational approaches directly incorporate the exact morphology using, for example, computed tomography of the materials of interest [4][5][6][7][8].…”

Section: Introductionmentioning

confidence: 99%

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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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Section: Radiative Heat Transfermentioning

confidence: 99%

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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“…More recently, Coquard et al [31] investigated experimentally the coupled heat transfer in metallic and ceramic open-cell foams at high temperatures from 293 K to 673 K. They manage to estimate both conductive and radiative contributions from a unique experiment by developing an identification method using thermograms obtained from laser-FLASH measurements applied to foam samples. The analysis of the thermograms of several NiCrAl, FeCrAl, Mullite and PsZ foams showed that for metallic foams, the conductive contributions increases noticeably with temperature due to the increase of the solid phase conductivity whereas it remains practically unchanged for ceramic foams.…”

Section: Coupled Heat Transfermentioning

confidence: 99%

“…To overcome these experimental difficulties, we have recently proposed [31] an innovative method of evaluation of the conductive and radiative contributions from a unique transient experiment.…”

Section: Measuring the Conductive And Radiative Contributions To Heatmentioning

confidence: 99%

“…The direct simulation of the transient combined radiation-conduction heat transfer necessary for the identification is achieved using the discrete ordinates method and the finite volume method while the iterative gauss linearization method is employed to minimize the discrepancy. For more details about the methodology, the reader is encouraged to consult the original paper [31]. The method developed was applied to several ceramic and metallic foam samples on which laser-FLASH measurements were conducted at the CEA Le Ripault [31].…”

Section: Measuring the Conductive And Radiative Contributions To Heatmentioning

confidence: 99%

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Conductive and Radiative Heat Transfer in Ceramic and Metal Foams at Fire Temperatures

Coquard¹,

Rochais

Baillis

2010

Fire Technol

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In addition to the multiple actual or possible applications of metal and ceramic foams in various technological fields, their thermal properties make them a good candidate for utilization as fire barriers. Several studies have shown experimentally their exceptional fire retardance due to their low apparent thermal conductivity. However, while the thermal properties of this porous material have been widely studied at ambient temperature and are, at present, well-known, their thermal behaviour at fire temperatures remains relatively unexplored. Indeed, at such temperatures, the major difficulties are not only due to the fact that thermal measurements are rendered fussy since heavy equipments are required but also stem from the fact that a significant part of the heat transfer occurs by thermal radiation which is much more difficult to evaluate than conductive heat transfer. Therefore, the present chapter is written with a view to report progress on the knowledge of heat transfer in open cell foams and to enlighten the reader on the mechanisms of heat transfer at high temperatures. A first part is devoted to the review of the prior published works on the experimental or theoretical characterisations of radiative and conductive heat transfers from ambient to high temperatures. By taking inspiration from the concepts and models presented in these previous works, we propose, in a second part, a model of prediction of the conductive and radiative contributions to heat transfer at fire temperatures. This analytical model is based on numerical simulations applied to real foams and takes into account the structure of the foam and the optical and thermal properties of the constituents. In a third part, we propose an innovative experimental technique of characterization of heat transfer in foams at high temperatures which 12 permit to evaluate independently the radiative and conductive contributions from a unique and simple measurement. The experimental results obtained on several metal and ceramic foams are compared to the results predicted by our numerical model. The good adequacy between experimental and theoretical results show the consistency of both approaches.

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Physicochemical processes in the zone of local laser heating of porous aluminosilicate ceramics

Aguilar

Власова

Bernal

et al. 2021

Int J Ceramic Engine & Sci

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The performed investigations have shown that the basis of the local laser heating/"drilling" of composite coarse-pored ceramics consisting of aluminosilicates and a glass phase is the melting and ablation processes that lead to the formation of a hole. The interaction of the components of the composite in the zone of high-temperature heating is accompanied by the formation of melt of a glass phase of new composition. The motion of the metal to the depth of a sample through pore channelsclusters of the main ceramic material depends on the viscosity of melt (i.e., on the radiation regime) and the cooling rate of the melt (i.e., the thermo physical properties of the ceramics and glass phase). The development of hydrodynamic pressure in the zone of laser heating leads not only to the ejection of a part of the melt from the channel, but also to the densification of the ceramics adjacent to the Accepted Article This article is protected by copyright. All rights reserved walls of the vitrified channel. These effects depend to a great extent on the ceramics/glass phase ratio and on the porosity of the initial ceramics.

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Experimental investigations of the coupled conductive and radiative heat transfer in metallic/ceramic foams

Cited by 88 publications

References 27 publications

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

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

Conductive and Radiative Heat Transfer in Ceramic and Metal Foams at Fire Temperatures

Physicochemical processes in the zone of local laser heating of porous aluminosilicate ceramics

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