Affiliation:
1. Cerema, Université Gustave Eiffel
2. Univ. Gustave Eiffel
3. Cerema
4. Université de Lyon
5. Université Gustave Eiffel
Abstract
Biosourced materials such as vegetal wools offer major thermal insulation advantages in the green buildings field. Experimental characterisations of vegetal wools thermal conductivity as a function of their density show the existence of an optimum conduction-radiation coupled value. This specific point, as well as the properties of vegetal wools are related to the large variability of shapes and sizes of their fibres. In order to take this specificity into account, it seems particularly relevant to use micro-macro modelling methods to predict the thermal conductivities related to both conduction and radiation heat transfer phenomena. In a first time, a self-consistent method based on a cylindrical geometry (SCMcyl) is used as a modelling approach for conduction transfers. Then, a modelling approach developed by Bankvall and based on an equivalent fibre radius value is used for radiation transfers. So, by coupling these two approaches, it is possible to obtain an equivalent thermal conductivity of fibrous materials as a function of density. Finally, this method is validated by comparison with experimental data.
Publisher
Trans Tech Publications Ltd
Reference32 articles.
1. Arnaud L., Cérezo V., 2001. Qualification physique des matériaux de construction à base de chanvre. Rapport technique CNRS 0711462, ENTPE.
2. Auriault J-L., 1991. Heterogeneous medium. Is an equivalent macroscopic description possible ? International Journal of Engineering Science, 29 (7), 785–795.
3. Bankvall C., 1973. Heat transfer in fibrous materials, J. Test. Eval. 1 (3), 235–243, https://doi.org/10.1520/JTE10010.
4. Bomberg M., Klarsfeld S., 1983. Semi-empirical model of heat transfer in dry mineral fiber insulations, J. Therm. Insul. 6 (3), 156–173.
5. Boutin C., 1996. Conductivité thermique du béton cellulaire autoclavé: modélisation par méthode autocohérente, Matériaux et Constructions 29 (6), 609–615, https://doi.org/10.1007/BF02485968.