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Article Dans Une Revue International Journal of Thermal Sciences Année : 2024

Thermal conductivity parallel and perpendicular to fibers direction and heat capacity measurements of eight wood species up to 160 °C

Résumé

The aim of this work was to characterize the thermal properties of wood prior to pyrolysis. The Anisotropic Parallel Hot Wire (APHW) technique was applied to characterize 8 wood species with densities varying between 100 and 1000 kg m−3. This variant of the hot wire technique allows the simultaneous measurement of the transverse and longitudinal thermal conductivity and the volumetric heat capacity of wood. Measurements were performed at 4 different temperatures: 20, 60, 110 and 160 °C. The results show that the thermal conductivity in both directions is independent of the type of wood (hardwood or softwood) and it increases linearly with density. Furthermore, the measurements show that the transverse thermal conductivity increases with temperature in contrast to the longitudinal conductivity which is either independent or decreases slightly with the temperature. Therefore, the anisotropy factor decreases with the temperature. The effect of water was also studied by characterizing the same samples at 20 and 60 °C, wet (water content 10%) and dried. The latter results show that thermal conductivity increases with the moisture content. Meanwhile, the effect of water is larger in the transverse direction. The heat capacity was also measured by the Differential Scanning Calorimetry (DSC) technique between 20 and 90 °C every 10 °C. The latter measurements show that the heat capacity is independent of the density and the wood species. It increases linearly with temperature for all wood species.

Dates et versions

hal-04411172 , version 1 (23-01-2024)

Identifiants

Citer

Hassan Flity, Yves Jannot, Lucas Terrei, Paul Lardet, Vincent Schick, et al.. Thermal conductivity parallel and perpendicular to fibers direction and heat capacity measurements of eight wood species up to 160 °C. International Journal of Thermal Sciences, 2024, 195, pp.108661. ⟨10.1016/j.ijthermalsci.2023.108661⟩. ⟨hal-04411172⟩
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