Theoretical Determination of Moisture and Heat Transfer To Lumber During Preheating
Keywords:Chemical potential, heat transfer, moisture transfer
AbstractTwo-dimensional heat and mass flux equations were used to describe preheating process during wood drying. Mathematical formulae of heat and moisture transfer to wood were developed. Based on the theoretical calculation, the increase in lumber moisture content (MC) was less than 8% during the preheating process. The calculated results also indicated that it takes about 3 h for the center of 4-cm-thick lumber to reach ambient temperature.
Allxiou, P. N., A. P. Wilkins, and J. Hartley. 1990a. Effect of pre-streaming on drying rate, wood anatomy, and shrinkage of regrowth Eucalytus pilularis Sm.Wood Sci. Technol. 24(1): 103-110.nAllxiou, P. N., J. F. Marchant, and K. W. Groves. 1990b. Effect of pre-streaming on drying rate, wood anatomy, and shrinkage of regrowth Eucalytus pilularis Sm.Wood Sci. Technol. 24(2):201-209.nBramhall, G. 1979. Mathematical model of lumber drying I. Principles involved. Wood Sci. 12(1):14-21.nDegroot, S. R. 1952. Thermodynamics of irreversible processes. North-Holland Publishing Co., Amsterdam, 38 pp.nGu, L., and P. Garrahan. 1984. The temperature and MC in lumber during preheating and drying. Wood Sci. Technol. 18(2):121-135.nHalsopoulos, G. H., and J. H. Keenan. 1981. Principles of general thermodynamics. Robert Krieger Publishing Company, New York, NY. 628 pp.nKollman, F. F. P., and W. A. Cote Jr. 1968. Principles of wood science and technology I. Solid wood. Springer-Verlag, Berlin. 246 pp.nNelson, R. M. Jr. 1986. Diffusion of bound water in wood Part 3: A model for non-isothermal diffusion. Wood Sci. Technol. 20(4):309-328.nNelson, R. M. Jr. 1989. Nonisothermal diffusion of moisture in wood. Pages 357-377 in C. Schuerch. ed. Cellulose Conference, Syracuse. John Wiley and Sons, New York, NY.nNelson, R. M. Jr. 1991. Heats of transfer and activation energy for bound water diffusion in wood. Wood Sci. Technol. 25(3): 193-202.nSiau, J. F. 1980. Nonisothermal moisture movement in wood. Wood Sci. 13(1):11-13.nSiau, J. F. 1984. Transport processes in wood. Springer-Verlag, Berlin. 218 pp.nSiau, J. F., and M. Babiak. 1983. Experiment on noniso-thermal moisture movement in wood. Wood Fiber 15(1):40-46.nSimpson, W. T. 1976. Effect of pre-steaming on moisture gradient of northern red oak during drying. Wood Sci. 8(4):272-278.nSkaar, C. 1988. Wood water relations. Springer-Verlag, Berlin, Heideberg, New York. 199 pp.nSkaar, C., and J. F. Siau. 1981. Thermal diffusion of bound water in wood. Wood Sci. Technol. 15(2):105-112.n
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