Parameter estimation of moisture transfer in wood

This study focuses on the bound water and liquid water transfer in wood and is to investigate moisture change and distribution of six wood species (three softwood and three hardwood) in the longitudinal direction exposed to the long term moisture sorption. This paper presents the results of experimental investigations of wood sorption in static environmental condition. Most of species used for the experiment arrived at estimated maximum moisture content and there might be no significant hysteresis in the capillary pressure curve due to air entrapment. The experimental data on the different samples were found to vary considerably. The Boltzmann transformation and Levenberg-Marquardt method were used to determine the liquid water diffusivity from measured moisture content profiles. For moisture content changes with time and moisture profiles, the validity was ascertained by comparing the numerical results with the corresponding experimental measurements. There was the abrupt change of the slope of the diffusivity function around fiber saturation point, which might seriously slow down the numerical solution process or even lead to a non-convergence condition.