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Comparison of Models for Heat Transfer in High-Density Fibrous Insulation



Sergio A. Carvajal, Edward Garboczi, Robert R. Zarr


This paper evaluates different models for calculating the effective thermal conductivity of fibrous insulation by comparing predicted values with certified values of Standard Reference Material 1450c, Fibrous Glass Board. The fiber diameter distribution was measured using X-ray computed tomography, since this distribution was needed for several of the thermal transfer theories considered in this paper. The coupled effect of radiation and conduction was examined. For the evaluation of the radiative heat transfer, the diffusion approximation, the Schuster- Schwarzschild approximation, and the Milne-Eddington approximation were considered. The conduction of the gas and the fibers was treated by the kinetic theory and a semi-empirical model, respectively. Two models were considered for the evaluation of the radiative properties: the large specular reflecting approach and the application of Mie theory for media composed by infinite cylinders.
Journal of Research (NIST JRES) -


conduction, fiber, insulation, models, radiation heat transfer, SRM 1450c, X-ray computed tomography


Carvajal, S. , Garboczi, E. and Zarr, R. (2019), Comparison of Models for Heat Transfer in High-Density Fibrous Insulation, Journal of Research (NIST JRES), National Institute of Standards and Technology, Gaithersburg, MD, [online],, (Accessed July 19, 2024)


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Created May 12, 2019, Updated October 12, 2021