| Автор | T Rettelbach |
| Автор | J Sauberlich |
| Автор | S Korder |
| Автор | J Fricke |
| Дата выпуска | 1995-03-14 |
| dc.description | The thermal conductivity of evacuated pure and opacified silica aerogel powders was measured in a guarded hot plate apparatus for temperatures from 10 K up to 275 K and external loads from 1.5*10<sup>4</sup> Pa to 10<sup>5</sup> Pa. Infrared optical measurements of the extinction give the possibility to separate contributions from solid thermal conduction and radiative thermal transport. Measured thermal conductivities range from 29 to 80*10<sup>-6</sup> W m<sup>-1</sup> K<sup>-1</sup> at a temperature of 15 K and from 0.9 to 3.1*10<sup>-3</sup> W m<sup>-1</sup> K<sup>-1</sup> at a temperature of 250 K. The solid thermal conductivities lambda <sub>powder</sub> of the powders were compared with those of the monolithic silica aerogel ( lambda <sub>monolith</sub>) the powder grains consist of. The ratio g'= lambda <sub>monolith</sub>/ lambda <sub>powder</sub> was found to be temperature independent in the investigated temperature range. Thus g' can be interpreted as a geometrically induced reduction factor. The mean thermal conductivities averaged over the application temperatures range from 0.7 to 2.2*10<sup>-3</sup> W m<sup>-1</sup> K<sup>-1</sup> for boundary temperatures of 77.6 and 290 K and from 0.5 to 1.8*10<sup>-3</sup> W m<sup>-1</sup> K<sup>-1</sup> for boundary temperatures of 20.4 and 290 K. The investigated silica aerogel powders show a large improvement potential for cryogenic thermal powder insulations. They are well suited to substitute expanded Perlite as cryo insulation. |
| Формат | application.pdf |
| Издатель | Institute of Physics Publishing |
| Название | Thermal conductivity of IR-opacified silica aerogel powders between 10 K and 275 K |
| Тип | paper |
| DOI | 10.1088/0022-3727/28/3/021 |
| Electronic ISSN | 1361-6463 |
| Print ISSN | 0022-3727 |
| Журнал | Journal of Physics D: Applied Physics |
| Том | 28 |
| Первая страница | 581 |
| Последняя страница | 587 |
| Аффилиация | T Rettelbach; Bayerisches Zentrum fur Angewandte Energieforschung, Wurzburg, Germany |
| Аффилиация | J Sauberlich; Bayerisches Zentrum fur Angewandte Energieforschung, Wurzburg, Germany |
| Аффилиация | S Korder; Bayerisches Zentrum fur Angewandte Energieforschung, Wurzburg, Germany |
| Аффилиация | J Fricke; Bayerisches Zentrum fur Angewandte Energieforschung, Wurzburg, Germany |
| Выпуск | 3 |
