%0 Research article
%T Use of combined constant rate and diffusion model to simulate kiln-drying of Pinus radiata timber
%A Youngman, M. J.
%A Kulasiri, G. D.
%A Woodhead, I. M.
%A Buchan, G. D.
%D 1999
%J Silva Fennica
%V 33
%N 4
%R doi:10.14214/sf.652
%U https://silvafennica.fi/article/652
%X This paper presents the use of a combined constant drying-rate and  diffusion model to simulate the drying of Pinus radiata timber under  kiln-drying conditions. The constant drying-rate and diffusion  coefficients of the model, which control the drying rate of individual  pieces of timber, were determined from calibrating the model against the  experimental drying curves obtained under the kiln-drying conditions.  The experimental drying curves were obtained from the gravimetric  measurements of the moisture content of timber during kiln drying.  Statistical relationships were developed for the constant drying-rate  and the diffusion coefficients of the model as functions of kiln  temperature and the dry basis density of timber. To determine the  effects of variability of timber, a simulation scheme was developed  based on the model, the probability distribution of the density of  timber, the equations for the constant drying-rate coefficient and the  diffusion coefficient. The model and the associated simulation method  provides a simple way to estimate the drying time of a stack of timber  using parameters determined from experimental results for the specific  timber kiln.