Theoretical modeling of thermal conductivity of alumina aerogel composites based on real microstructures

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review

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Author(s)

  • Shuo-Lin Wang
  • Zhe Jin
  • Jun-Ning Li
  • Ben-Xi Zhang
  • Yi-Bo Wang
  • Yan-Ru Yang
  • Xiao-Dong Wang

Detail(s)

Original languageEnglish
Pages (from-to)150-160
Journal / PublicationJournal of the Taiwan Institute of Chemical Engineers
Volume120
Online published7 Mar 2021
Publication statusPublished - Mar 2021
Externally publishedYes

Abstract

As compared with silica aerogels, alumina aerogels have excellent high-temperature stability, and hence, are regarded as a promising candidate for high-temperature thermal insulation materials. However, heat transfer mechanisms for such materials remain insufficiently explored. In this study, based on real material microstructures, an analytical thermal conductivity model for alumina aerogel-fiber-opacifier composites is developed via a modified parallel-series equivalent electrical circuit approach. The model takes into account solid, gaseous, and solid-gas coupling heat conduction in aerogels, solid heat conduction in both fibers and opacifier particles, and radiation in aerogels, fibers, and opacifier particles. The model is validated by comparing its predictions with measured thermal conductivity data. The model predictions reveal that there are two kinds of solid-gas coupling heat transfer mechanisms, which occur in the corner regions between interconnected secondary particles and in the slit regions between adjacent chains, respectively. Because of this coupling, the contribution of gaseous heat conduction is comparable to that of solid heat conduction and radiation of aerogels, fibers, and opacifier particles, which is well supported by experimentally measured data of thermal conductivity. The model is also used to analyze effects of various parameters on the thermal insulation performance of the composites, such as diameters and volume fractious of both fibers and opacifier particles.

Research Area(s)

  • Aerogel, Fiber, Opacifier, Solid-gas coupling, Thermal conductivity

Citation Format(s)

Theoretical modeling of thermal conductivity of alumina aerogel composites based on real microstructures. / Wang, Shuo-Lin; Jin, Zhe; Li, Jun-Ning et al.
In: Journal of the Taiwan Institute of Chemical Engineers, Vol. 120, 03.2021, p. 150-160.

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review