Mass transfer in wood evaluated with a colorimetric technique and numerical analysis

A colorimetric CoCl₂-treated wood technique was used for determining surface moisture content of wood nondestructively and continuously during unsteady state desorption conditions. Utilizing these surface moisture data, diffusion and surface emission coefficients have been determined simultaneously and continuously during drying. The conversion method, which has been developed to facilitate making comparison between mass transfer coefficients in this study, has proven that the boundary layer theory is useful for evaluating the external moisture resistance during wood drying. The moisture profiles simulated by the finite difference method were quite comparable to the actual moisture profiles in real dried wood, which substantiates the high credibility of using the colorimetric technique for determining surface moisture content and mathematical procedure for determining the diffusion and surface emission coefficient.