Effective Total Thermal Conductivity of Aerogels

In the case where heat transfer in aerogels depends on the local temperature gradient, the effective total thermal conductivity can be expressed as the sum of the soUd thermal conductivity of the solid backbcaie As, the effective thermal conductivity of the gaseous phase Ag, and finally, the radiative conductivity A,  

Since (23.16) is independent of direction, it is rally valid for aerogels with isotropic thermal properties. Many experimentally derived values for the thermal conductivity of aerogels under various conditions are available. Hrubesh et al. discussed the superposition 

Organic aerogels (Part IV) are of special interest due to their thermal insulation properties. The organic solid backbone has a low solid thermal conductivity in comparison to inorganic aerogels [27]. Heat transfer within resorcinol-formaldehyde (RF) aerogels 

Very low thermal conductivity values in the range of 0.011 Wm were determined [37] for RF-aerogels. The morphology of RF aerogels can be influenced by the mass ratio R C of resorcinol to the catalyst sodium carbonate and by the density of the RF aerogel. Differences in the morphology of RF aerogels are indicated by different colors of the 

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