Thermal conductivity of non-isotropic materials measured by various methods

Groß, Ulrich; Barth, Gerald; Wulf, Rhena; Tran, Le Thanh Son

doi:10.1068/htwu101

Cited by 7 publications

(4 citation statements)

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“…The latter situation is also found for the hot-wire measurements where the xy-, yz-, and xz-directions have been investigated. Two different ceramic fiber mat materials have been selected (Table 3), both cover wide ranges of their bulk density, and the first results have been reported by Gross et al [18] and Wulf et al [19].…”

Section: Results For Non-isotropic Fiber Mats Of Alumina and Alumino-mentioning

confidence: 99%

Intercomparison of Insulation Thermal Conductivities Measured by Various Methods

2007

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In the present contribution, systematic effective thermal-conductivity measurements with different methods are reported for various materials. One of the materials studied, calcium silicate, is isotropic; the other two, alumino-silicate and alumina fiber mats, are non-isotropic. The measurements were carried out with two different steady-state panel test apparatus (according to ASTM C201, designed and constructed by authors), two guarded hot-plate apparatus (ISO 8302, with either one or two samples), one steady-state radial heat flow apparatus (designed by authors), and one transient hot-wire instrument (DIN EN 993-14). These apparatus are operated at ambient pressure and atmosphere (air) between 20 and 1,650 • C, and are briefly described in the article. The results show the well-known increase of effective conductivity with temperature, mainly due to radiation heat transfer. For the case of the isotropic calcium silicate material (bulk density of 220 kg m −3 ), no significant differences between the various methods have been found and the results can easily be correlated within ±10%. The fiber-mat results, however, show additional effects of the density (between 103 and 170 kg m −3 ) and the fiber orientation. Large differences exceeding 30% are found between plate and hot-wire results.

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Section: Results For Non-isotropic Fiber Mats Of Alumina and Alumino-mentioning

confidence: 99%

Intercomparison of Insulation Thermal Conductivities Measured by Various Methods

2007

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“…The Heat-Flow-Meter [115,117] resembles the guarded hot plate, however, instead of directly measuring the energy input into the heating element a heat flux sensor is positioned between the sample and the cooling element. The panel test technique [104,[118][119][120] is another variation, where the heat flux is measured using a calorimeter that simultaneously acts as the cooling element. Compared to the guarded hot plate method, higher measurement temperatures can be achieved.…”

Section: Steady-state Methodsmentioning

confidence: 99%

Brief Review on Experimental and Computational Techniques for Characterization of Cellular Metals

Duarte

Fiedler

Krstulović‐Opara

et al. 2020

Metals

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“…There are several well-established methods for measuring thermal conductivity of insulation materials [39,40], but only a few of these methods are capable of conducting measurements at temperatures greater than 1273 K [21,41,42]. Generally, test methods are based on either transient or steady-state measurements.…”

Section: Test Methodsmentioning

confidence: 99%

Thermal conductivity of refractory glass fibres

Modarresifar

Bingham

Jubb

2016

J Therm Anal Calorim

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In the present study, the current international standards and corresponding apparatus for measuring the thermal conductivity of refractory glass fibre products have been reviewed. Refractory glass fibres are normally produced in the form of low-density needled mats. A major issue with thermal conductivity measurements of these materials is lack of reproducibility in the test results due to transformation of the test material during the test. Also needled mats are inherently inhomogeneous, and this poses additional problems. To be able to compare the various methods of thermal conductivity measurement, a refractory reference material was designed which is capable of withstanding maximum test temperatures (1673 K) with minimum transformation. The thermal conductivity of this reference material was then measured using various methods according to the different standards surveyed. In order to compare different materials, samples have been acquired from major refractory glass fibre manufacturers and the results have been compared against the newly introduced reference material. Materials manufactured by melt spinning, melt blowing and sol-gel have been studied, and results compared with literature values.

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Thermal conductivity of non-isotropic materials measured by various methods

Cited by 7 publications

References 1 publication

Intercomparison of Insulation Thermal Conductivities Measured by Various Methods

Intercomparison of Insulation Thermal Conductivities Measured by Various Methods

Brief Review on Experimental and Computational Techniques for Characterization of Cellular Metals

Thermal conductivity of refractory glass fibres

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