Comini and Lewis [2] and Thomas et al. [3] were amongst the first to develop a numerical model applied to timber Drying is a process which involves heat and mass transfer both inside the porous material, where a phase change in moisture occurs drying. The model incorporates the Luikov [4, 5] system of from the liquid to the gaseous state, and in the external boundary partial differential equations for a general capillary porous layer of the convected hot dry air, which heats the porous medium. body for the field variables of moisture content and temper-
The equations which govern this process consist of three tightly ature. The pressure was assumed constant throughout the coupled, highly non-linear partial differential equations for the undomain of interest and moisture transfer under the influknown system variables of moisture content, temperature, and pressure. Due to the inherently complex boundary conditions and ence of a pressure gradient was assumed to be negligible.
intricate physical geometries in any practical drying problem, an
For high temperature drying problems, Ferguson [6] analytical solution is not possible. In order to obtain a transient showed that the pressure term induced a significant mass drying solution it is necessary to resort to a numerical technique.
transfer. The computational solution technique which was
Earlier researchers in this field have employed finite difference, finite element, and cell-centered control volume computational models to utilised to solve the governing equations was the finite obtain a numerical solution to this complex problem. This paper element method. Dahlblom et al. [7] and Felix and Morlier presents a novel application of the hybrid control volume finite [8] independently developed Whitaker [9] style drying element scheme, which will lay the foundations for the solution of models for timber which employed the finite element a timber drying problem on a deforming mesh. In order to test the method as the numerical solution technique. performance of the simulation code over a range of differing drying conditions, numerical solutions to two timber drying problems are Michel et al. [10], Moyne and Perre [11, 12], Perre [13],
presented in this paper: first, a low temperature drying case with and Turner [14] developed timber drying models based on a dry bulb temperature of 80ΠC, and, second, for a case where an averaging volume, proposed by Whitaker [9], across the dry bulb temperature is above the boiling point of water at which material parameters could be measured. The com-120ΠC.