A mesoscopic drying model applied to the growth rings of softwood: mesh generation and simulation results

Abstract

A mesoscopic drying model that enables the drying simulation of quartersawn and fl atsawn wood sections consisting of several growth rings is presented. The procedure to generate the virtual board description directly from real sample images is also described. This virtual structure accommodates the prominent sample features, including its geometrical and physical properties, together with the density and structural variation across the growth rings. We give a synopsis of the sophisticated techniques developed specifi cally to generate this virtual description and exhibit the fi nal computational meshes produced by the software for quartersawn and fl atsawn sections. Low temperature drying simulations are then performed for both heterogenous and homogeneous model variants using these virtual descriptions and comparisons are made of the resulting MC fi eld evolution. A highlight of these comparisons is that the heterogeneous model captures realistic drying effects, including the fast drying of earlywood and the late removal of liquid water in latewood. In comparing the drying of quartersawn and fl atsawn boards we conclude that the effect of the heterogeneous nature of the MC fi elds is diminished somewhat when considering the fl atsawn section over the quartersawn section.

Multiscale Modeling of Drying as a Powerful Extension of the Macroscopic Approach: Application to Solid Wood and Biomass Processing

“…Figure 8 depicts an example of the mesoscopic approach used to simulate the drying of a section of softwood containing some annual growth rings. [24] The nonuniform [24] ). APPLICATION TO SOLID WOOD AND BIOMASS PROCESSING initial moisture content field is a direct effect of the spatial variation of the capillary function curve.…”

Characterisation of wood–water relationships and transverse anatomy and their relationship to drying degrade

“…Then, Eq. (5) is fitted to the desorption/sorption data in the least-squares sense by solving for c 1 and c 2 as reported by Perré and Turner (2008):…”

A New Control‐Volume Finite‐Element Scheme for Heterogeneous Porous Media: Application to the Drying of Softwood

“…As mentioned earlier, the heterogeneity of the wood is captured in the model through the density variation of material properties that feature in the equations. For the complete set of correlations used in this model formulation the reader is referred to [4,9,10].…”

“…All of the aforementioned facts highlight the strong heterogeneity of wood and the challenge that mathematically model- ing the drying of wood presents. Drying models that account for this heterogeneity have appeared in the relevant literature during the last two decades (see, e.g., [2][3][4][5][6][7][8]). In particular, the work by two of the current authors, Perré and Turner [2], saw a previously developed homogeneous drying model consisting of three nonlinear, coupled partial differential equations modified to account for the variation in wood density (see Sect.…”