Wood Thermal Properties Testing Of Experimental And Theoretical Study

Wood is a kind of typical combustible substance. In order to research the microcosmic mechanism of fire, it is very necessary to study the thermophysical properties of wood. So it is significant to research the measurement of the wood thermophysical property.In this paper, 1-dimension unsteady heat conduction model has been developed under the second boundary condition, and its analytical solution at quasi-stable state is obtained. But there is some error when applying the analytical solution to work out the wood thermophysical property directly.Then the experimental study has been performed on the quasi-stable state thermophysical property test devices. In order to obtain the thermal conductivity, specific thermal capacity and thermal diffusivity of red pine, larch and Eucalyptus Saligna, some experiments under the different conditions have been carried out respectively.A quasi-stable state thermophysical property test calculation model has been established to simulate the wood, which were heating, by the ANSYS software. The temperature distribution and heat flux field in the wood can be achieved by comparing the simulation results to the experimental data. At the same time, the effects of wood type and its temperature and moisture content on the thermophysical parameter were also investigated.After that, some useful conclusions have been attained: While the wood temperature increases from 35Cto 85C, the thermal conductivity of wood increases with the temperature, and then becomes decreasing, with that, it has a peak at 70C~80C. Moreover, the specific heat is increasing continuously in the same temperature range, while the thermal diffusivity of the wood is decreasing at all times. Meanwhile, the thermal conductivity and specific heat increases with wood moisture content, but the thermal diffusivity decreases with the change of moisture.In this paper, the error analysis of the quasi-stable thermophysical property test has been given. The maximal relative deviations of the wood thermal conductivity is 1.77%, specific heat 2.15%~3.55% and thermal diffusivity2.4%~3.6%.