Mass Transfer in Wood Evaluated with a Colorimetric Technique and Numerical Analysis

Authors

  • Hwanmyeong Yeo
  • William B. Smith
  • Robert B. Hanna

Keywords:

Mass transfer, diffusion, surface emission, boundary layer theory, finite difference method, colorimetric technique

Abstract

A colorimetric CoCl2-treated wood technique was used for determining surface moisture content of wood nondestructively and continuously during unsteady state desorption conditions. Utilizing these surface moisture data, diffusion and surface emission coefficients have been determined simultaneously and continuously during drying. The conversion method, which has been developed to facilitate making comparison between mass transfer coefficients in this study, has proven that the boundary layer theory is useful for evaluating the external moisture resistance during wood drying. The moisture profiles simulated by the finite difference method were quite comparable to the actual moisture profiles in real dried wood, which substantiates the high credibility of using the colorimetric technique for determining surface moisture content and mathematical procedure for determining the diffusion and surface emission coefficient.

References

Choong, E. T., and C. Skaar. 1969. Separating internal and external resistance to moisture removal in wood drying. Wood Science1(4):200-202.nChoong, E. T., and C. Skaar. 1972. Diffusivity and surface emissivity in wood drying. Wood Fiber4(2):80-86.nCIE. 1986. Colorimetry, 2nd ed. CIE Pub. No. 15.2. Commission Internationale de l'Eclairage, Vienna, Austria. 74 pp.nCrank, J. 1975. The mathematics of diffusion, 2nd ed. Clarendon Press, Oxford, UK. 414 pp.nGeankoplis, C. J. 1993. Transport process and unit operations, 3rd ed. Prentice Hall Inc., Englewood Cliffs, NJ. 921 pp.nSiau, J. F. 1995. Wood: Influence of moisture on physical properties. Dept. of Wood Science and Forest Products, Virginia Tech., Blacksburg, VA. 227 pp.nYeo, H. 2001. Evaluation of mass transfer in wood utilizing a colorimetric technique and numerical analysis. Ph.D. thesis, SUNY—ESF, Syracuse, NY. 200 pp.nYeo, H., W. B. Smith, and R. B. Hanna. 2002. Determination of surface moisture content of wood utilizing a colorimetric technique. Wood Fiber Science34(3):419-424.n

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Published

2007-06-05

Issue

Number 4 / October 2002

Section

Research Contributions

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