Estimation of Thermal Moisture Diffusivity from Liquid Redistribution Measurements

Experiments are performed to estimate the thermal liquid diffusivity of water in cork. ne isothermal liquid diffusivity, the moisture content dependent thermal conductivity and the sorption isotherm are measured in separate experiments. A heat and moisture transfer model is used to interpret the experimental data. The error between the measured and predicted moisture distributions is minimized to obtain the best estimate of the thermal liquid diffusivity. The value obtained is 2.1-10(-9) kg/m(.)s(.)K. The dominant mode of moisture redistribution is the transfer due to the temperature gradient in the material. The ratio of the effective thermal moisture diffusivity to the thermal vapor diffusivity varies from about 2 to 4. The material property that has the most significant impact on the heat flux is the moisture content-dependent thermal conductivity. The contribution of condensation/evaporation processes associated with vapor diffusion to the effective thermal conductivity is less than 5 percent.