THERMAL CONDUCTIVITY AND THERMAL DIFFUSIVITY MEASUREMENTS OF WOOD IN THE THREE ANATOMIC DIRECTIONS USING THE TRANSIENT HOT-BRIDGE METHOD.

In this paper, anisotropic wood is thermally characterized using the transient hot-bridge method recently developed at PTB Germany. The main element of this method is the THB sensor which is composed of four tandem strips forming a Wheatstone bridge and which has the specificity of measuring in the same experiment both thermal conductivity and thermal diffusitnty. The adoption of special configurations allows us to characterize anisotropic materials. In this context, the axial, radial, and tangential thermal conductivities as well as the thermal diffusivities of three wood species are measured and analyzed for different moisture contents. Due to the difficulty of measuring thermal diffusivity using the conventional electrothermal methods, particular care will be given to this task. Thus, the paper will focus on the analysis of thermal diffusivity versus moisture content, as well as on its relation to thermal conductivity. [ABSTRACT FROM AUTHOR]