Analysis and modeling of the pore size effect on the thermal conductivity of alumina foams for high temperature applications

Pelissari, P.I.B.G.B.; Angélico, Ricardo Afonso; Salvini, V. R.; Vivaldini, D. O.; Pandolfelli, V. C.

doi:10.1016/j.ceramint.2017.07.035

Cited by 70 publications

(23 citation statements)

References 25 publications

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“…While it is true that the foam layer tends to insulate the cold cap from the melt pool below, this is through its effect on T B that the foam controls the heat flux permitted to enter from the melt pool, and thus, by Equation (), the melting rate, but not through the heat conductivity that depends on the gas‐phase content in foam (foam porosity). This situation is thus different from the insulating foam layer on glass‐melt free surface, foam glass for insulation material, or in ceramic foams, where the fixed foam layer thickness controls the heat flux on which it is independent.…”

Section: Discussionmentioning

confidence: 98%

Glass production rate in electric furnaces for radioactive waste vitrification

et al. 2019

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Correlating the melting rates of feeds in electric melters with results of simple laboratory experiments can help evaluate melter feed additives and their effects on melting rate, and support the feed scheduling and plant operation. A recently proposed melting rate correlation (MRC) equation, relating the melting rate to melt viscosity, feed‐to‐glass conversion heat, and cold‐cap bottom temperature, was tested using data from experiments covering various feed compositions and melter operating parameters. The MRC equation is shown to reasonably represent the measured data and thus can be used to quantify how individual variables (melt viscosity, cold‐cap bottom temperature, conversion heat, melter operating temperature, and bubbling flux) affect the glass production rate.

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Section: Discussionmentioning

confidence: 98%

Glass production rate in electric furnaces for radioactive waste vitrification

et al. 2019

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“…By definition, they comprise a refractory matrix containing pores with a diameter greater than 50 nm, which are present in a volumetric fraction above 40% [10,11]. This microstructure is able to halt both the heat transference by phonons, due to the discontinuities in the solid crystalline lattice (pores), and by radiation, as pores in the range of 0.5 μm to 3 μm can interact with electromagnetic waves in the infrared spectra, spreading them [12].…”

Section: Introductionmentioning

confidence: 99%

Al2O3–CaO macroporous ceramics containing hydrocalumite-like phases

Borges

Santos

Salvini

et al. 2020

Ceramics International

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A mechanism to explain the lower onset strengthening temperature induced by CaCO3 in alumina-based macroporous ceramics is proposed, which relies on hydrocalumite-like phase formation during processing. Close to 600 °C, such phases are decomposed to lime and mayenite (12CaO·7Al2O3), where the latter, due to its intrinsic nanoporosity and high thermal reactivity, generates bonds between the ceramic particles at ~700ºC, resulting in microstructure strengthening. Based on this premise, the authors concluded that other Ca 2+ sources could act similarly. Indeed, compositions containing Ca(OH)2 or CaO showed the same effect on the onset strengthening temperature, which reinforces the proposed mechanism. The results attained indicated that macroporous insulators could be thermally treated at lower temperatures, just to acquire enough mechanical strength for installation, finishing in-situ their firing process. Besides that, lower sintering temperatures could be used to produce macroporous ceramics that would be applied in low thermal demand environments, e.g. aluminum industries.

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“…Illustrative plot of k cond , k conv , k rad , and k eff as a function of the temperature. Adapted from (23)…”

Section: Fundamentals On Heat Transportmentioning

confidence: 99%

Review: Thermal ceramic coatings as energy saving alternatives for high temperature processes

Sako

Orsolini

Moreira

et al. 2020

Int J Applied Ceramic Tech

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Reductions in energy consumption for high temperature processes are an important research topic, especially due to the ongoing energy crisis scenario. Based on the several possibilities of saving it, thermal coatings are an economical and technical viable possibility of tailoring the optical properties of a material surface. Although many studies have been published on the benefits of high emissivity and high reflectivity ceramic coatings, there is still a lack of a clear understanding on the correlation between thermal radiation heat transfer, solid state physics, and material science technology. This study aims to create a connection between these areas in order to provide basic guidelines for the correct use of thermal ceramic coatings, leading to achieving the maximum decrease in energy consumption by their use.

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Analysis and modeling of the pore size effect on the thermal conductivity of alumina foams for high temperature applications

Cited by 70 publications

References 25 publications

Glass production rate in electric furnaces for radioactive waste vitrification

Glass production rate in electric furnaces for radioactive waste vitrification

Al2O3–CaO macroporous ceramics containing hydrocalumite-like phases

Review: Thermal ceramic coatings as energy saving alternatives for high temperature processes

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