Determination of Effective Coefficient of Chinese Fir (Cunninghamia Lanceolata) During Adsorption and Desorption Process

Establishing an accurate moisture transport model in wood is essential to analyze the hygroscopic behavior and estimate the stability of wood structures in the ambient environment. In this article, the effective diffusion coefficients (EDCs) of Chinese fir in radial and tangential directions during absorption and desorption processes were measured based on the differential model, and numerical simulations were performed to verify the rationality of measured results. The results show that 1) for adsorption process, the surface emission coefficient (SEC) and EDC of Chinese fir are all greater in the radial direction; 2) for desorption process, the SEC is higher in the radial directions, whereas the EDC in the tangential direction is higher than that in the radial direction when the MC is greater than 10%; 3) the SEC and EDC in the adsorption process are larger than those in the desorption process. Because there is a reasonable agreement between experimental and mumerical simulation results, the measured results could be used to predict the MC distribution of Chinese fir in the ambient environment