Effective conductivity of porous ceramics in a radiative environment

Mora-Monteros, Jeremy; Suter, Clemens; Haussener, Sophia

doi:10.1016/j.ceramint.2019.09.272

Cited by 16 publications

(4 citation statements)

References 30 publications

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“…From a thermal viewpoint, the effective heat transfer within macroporous materials which operate at high temperatures (i.e., >800 K) may involve all three modes of heat transfer namely conduction, convection, and radiation. Such heat transfer and its key quantity Effective Thermal Conductivity (ETC) is generally influenced by textural parameters such as shape, size, orientation, and spatial distribution of constituents [12], the porosity of the material [13] as well as on the operational conditions [14]. Moreover, at high temperatures, different modes of heat transfer are generally coupled i.e., heat transfer by one mode might be affected by other mode making their effective contribution non-linear [11,15].…”

Section: Introductionmentioning

confidence: 99%

A modified zonal method to solve coupled conduction-radiation physics within highly porous large scale digitized cellular porous materials

et al. 2023

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Due to their distinct textures, porous cellular materials have been of interest to many engineering applications. Energy conversion through such materials, especially at high temperatures, is governed by naturally coupled conduction-radiation physics. Therefore, a thorough understanding of the conduction-radiation behavior within these materials is important to properly design and optimize these materials. Several numerical methods developed over the last few decades allow to solve and study the influence of different textural parameters on coupled conductive-radiative heat transfers. These numerical methods require 3D digitized images of the sample of interest obtained either using 3D imagery technique or generated using numerical algorithms. To better represent the complex geometry, the 3D image of the sample requires high spatial resolution, and for a sample which is representative of involved physics might contain hundreds of millions of voxels which is complex to solve and computationally expensive.To cope with this issue, we developed a parallelized discrete scale numerical approach using cell centered Finite Volume Method (FVM) and deterministic ray tracing to solve coupled heat transfer within highly porous large scale complex cellular materials. At the heart of this method rests a decomposition approach based on modified zonal method which significantly reduces the coupling efforts, memory requirements, and computation time. The results of two test cases presented in this study are cross-verified with those presented in literature and computed using Star-CCM+ software. Finally, the method is applied to virtual fibrous sample. These results present the ability of the solver to consider different boundary conditions, large temperature gradient across boundaries, and dealing with large samples consisting hundreds of million of voxels while providing accurate results. We also present and discuss the sensitivity of other associated parameters on the final results.

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Section: Introductionmentioning

confidence: 99%

A modified zonal method to solve coupled conduction-radiation physics within highly porous large scale digitized cellular porous materials

et al. 2023

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“…Thermal properties of porous materials are in focus of many ongoing research activities. There has been a growing interest in applying the LFA technique to measure metal and ceramic foams [8,9,10], coal [11], zeolites [12], concrete [13,14] and other promising materials. At the same time, reports exist of thermal conductivity measured in the transient plane source (TPS) method [15] and the guarded hot plate method (GHP) [16] being dependent on the gas chamber atmosphere.…”

Section: Introductionmentioning

confidence: 99%

Experimental evidence of gas-mediated heat transfer in porous solids measured by the flash method

Lauerer¹,

Lunev

2023

International Journal of Thermal Sciences

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“…The general formula of β-SiAlON, solid solution based on β-Si 3 N 4 , is given as Si 6-z Al z O z N 8-z (0 ≤ z ≤ 4.2), where z value corresponds to the extent of the Al-O bonds dissolved in the Si 3 N 4 structure [4]. It is well known that the porous ceramics represent a new family of ceramic materials, which can be widely used in filters for gases and liquids, purification and separation, catalyst carriers, shock absorption, advanced insulation materials, biological implant materials, sensor materials, and other applications due to their excellent properties, such as uniformly distributed micropores, high porosity, low density, selective permeability to liquids and gases, energy absorption, and dumping characteristics [5][6][7][8]. The radome is an important component of the high-speed aircraft.…”

Section: Introductionmentioning

confidence: 99%

Preparation of porous β-SiAlON ceramics using corn starch as pore-forming agent

Liu

Chen

et al. 2022

J Aust Ceram Soc

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In this study, porous β-SiAlON ceramics were prepared by starch consolidation using corn starch as a pore-forming agent. The effect of corn starch content (10 wt.%, 20 wt.%, and 30 wt.%) on the microstructure, apparent porosity, compressive strength, and dielectric properties of porous β-SiAlON ceramics was investigated. It was observed that both β-SiAlON and corundum phases were present in the prepared porous β-SiAlON ceramics. Meanwhile, the SEM results revealed that the hierarchical pore structures were formed as the corn content was enhanced. Increasing the corn starch content from 10 to 30 wt.% enhanced the apparent porosity from 53 to 64%, whereas the compressive strength decreased from 6.5 to 3.8 MPa. The porous β-SiAlON ceramics consisting of 60 wt.% solid content and 30 wt.% corn starch possessed porosity of 64%, reasonable compressive strength of 3.8 MPa, low dielectric constant of 3.0, and low dielectric loss tangent of 0.0046. Overall, the obtained results confirm that the starch consolidation method is a simple and convenient approach for preparing porous β-SiAlON ceramics with potential application in the field of radome.

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Effective conductivity of porous ceramics in a radiative environment

Cited by 16 publications

References 30 publications

A modified zonal method to solve coupled conduction-radiation physics within highly porous large scale digitized cellular porous materials

A modified zonal method to solve coupled conduction-radiation physics within highly porous large scale digitized cellular porous materials

Experimental evidence of gas-mediated heat transfer in porous solids measured by the flash method

Preparation of porous β-SiAlON ceramics using corn starch as pore-forming agent

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