A Control-Volume procedure compared with the Finite-Element method for calculating Stress and Strain during Wood Drying

ABSTRACT

This paper proposes a suitable method for calculating drying stresses. This is an application of the finite element method (FE) and the so-called control volume (CV) method. The latter has been chosen because most of coupled heat and mass transfer codes are based on CV.

A parallel between the resulting formulation and a particular case of FE method (quadrilateral four-nodes element and Galerkin's method) has been established Both analytical expressions and numerical results were compared. Furthermore, it is shown how to choose interpolation coefficients in CV procedure in order to get exactly the results obtained with FE.

Such a stress calculation has been added to the code TRANSPORE in order to obtain a complete drying code which, in addition to heat and mass transfers, solves stress and strain due to shrinkage, Interesting and promising simulations of non-symmetric convective drying are presented. Indeed, for this drying configuration, the stresses induce a global curvature of the section.

Keywords and Phrases:

• Control Volume
• Drying Stress
• Finite Element
• Modelling
• Non-symmetric drying
• Numerical Simulations