Two-Dimensional Finite Element Heat Transfer Model of Softwood. Part III. Effect of Moisture Content on Thermal Conductivity
Keywords:
Finite element modeling, thermal conductivity, moisture content, heat transfer, cellular structure, geometric modelAbstract
The anisotropy of wood creates a complex problem for solving heat and mass transfer problems that require analyses be based on fundamental material properties of the wood structure. Most heat transfer models for softwood use average thermal properties across either the radial or tangential direction and do not differentiate the effects of cellular alignment or differences in earlywood and latewood. A two-dimensional finite element model that considers these basic structural characteristics was developed to determine the effective thermal conductivity as a function of cell alignment, cell porosity, and moisture content. This paper extends the initial model to include moisture content effects from the oven-dry to the fully saturated condition. The model predicts thermal conductivity values as a function of density and moisture content. Comparisons are made with established empirical equations found in the literature for the thermal conductivity of wood. The models developed in this study series are useful for enhancing our understanding of fundamental heat transfer effects in various wood boards.References
ANSYS. 2004. Finite element software. ANSYS, Inc. Southpointe, Canonsburg, PA.nGu, H. M. 2001. Structure based, two-dimensional anisotropic, transient heat conduction model for wood. PhD dissertation, Department of Wood Science and Forest Products, Virginia Tech, Blacksburg, VA. 242 pp.nHart, C. A. 1964. Theoretical effect of gross anatomy upon conductivity of wood. Forest Prod. J.14(1):25-32.nHendricks, L. T. 1962. Thermal conductivity of wood as a function of temperature and moisture content. MS thesis, SUNY College of Forestry, Syracuse, NY. 83 pp.nIerardi, J. A. 1999. A computer model of fire spread from engine to passenger compartments in post-collision vehicles. MS thesis, Worcester Polytechnic Institute, Fire Protection Engineering, Worcester, MA. 205 pp.nIncropera, F. P., and D. P. DeWitt. 1981. Fundamentals of heat and mass transfer. 4th ed. John Wiley & Sons, New York, NY.nKohlmann, G. 1962. Investigation of the thermal properties of wood and particleboard in dependency on moisture content and temperature in the hygroscopic range. Holz Roh-Werkst.20(7):259-270.nMacLean, J. D. 1941. Thermal conductivity of wood. Heating, Piping, Air Conditioning13:380-391.nSiau, J. F. 1995. Wood: Influence of moisture on physical properties. Department of Wood Science and Forest Products, Virginia Tech, Blacksburg, VA. 227 pp.nStamm, A. J. 1960. Bound-water diffusion into wood in across the fiber directions. Forest Prod. J.10:524-528.nWangaard, F. F. 1943. The effect of wood structure upon heat conductivity. ASME Trans.65:127-135.n
Downloads
Published
Issue
Section
License
The copyright of an article published in Wood and Fiber Science is transferred to the Society of Wood Science and Technology (for U. S. Government employees: to the extent transferable), effective if and when the article is accepted for publication. This transfer grants the Society of Wood Science and Technology permission to republish all or any part of the article in any form, e.g., reprints for sale, microfiche, proceedings, etc. However, the authors reserve the following as set forth in the Copyright Law:
1. All proprietary rights other than copyright, such as patent rights.
2. The right to grant or refuse permission to third parties to republish all or part of the article or translations thereof. In the case of whole articles, such third parties must obtain Society of Wood Science and Technology written permission as well. However, the Society may grant rights with respect to Journal issues as a whole.
3. The right to use all or part of this article in future works of their own, such as lectures, press releases, reviews, text books, or reprint books.
