Advertisement

Effects of the method of identification of the diffusion coefficient on accuracy of modeling bound water transfer in wood

  • Wieslaw Olek
  • Jerzy Weres
Chapter

Abstract

An alternative approach to determining the bound water diffusion coefficient is proposed. It comprises a method for solving the inverse diffusion problem, an improved algorithm for the bound-constrained optimization as well as an alternative submodel for the diffusion coefficient’s dependency on the bound water content. Identification of the diffusion coefficient for Scots pine wood (Pinus sylvestris L.) using the proposed inverse approach is presented. The accuracy of predicting the diffusion process with the use of the coefficient values determined by traditional sorption methods as well as by the inverse modeling approach is quantified. The similarity approach is used and the local and global relative errors are calculated. The results show that the inverse method provides valuable data on the bound water diffusion coefficient as well as on the boundary condition. The results of the identification can significantly improve the accuracy of mass transfer modeling as studied for drying processes in wood.

Keywords

Inverse method Computer-aided identification Fick’s law Scots pine wood Sorption experiments Validation of identification 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. Choong, E. T., Skaar, C.: Separating internal and external resistance to moisture removal in wood drying. Wood Sci. 1, 200–202 (1969)Google Scholar
  2. Choong, E. T., Skaar, C.: Diffusivity and surface emissivity in wood drying. Wood Fiber 4, 80–86 (1972)Google Scholar
  3. Crank, J.: The Mathematics of Diffusion. Clarendon Press, Oxford (1975)Google Scholar
  4. Liu, J. Y.: A new method for separating diffusion coefficient and surface emission coefficient. Wood Fiber Sci. 21, 133–141 (1989)ADSGoogle Scholar
  5. Newman, A. B.: The drying of porous solids: diffusion and surface emission equations. Trans. AIChE 27, 203–220 (1931)Google Scholar
  6. Olek, W., Weres, J., Guzenda, R.: Effects of thermal conductivity data on accuracy of modeling heat transfer in wood. Holzforschung 57, 317–325 (2003)CrossRefGoogle Scholar
  7. Olek, W., Perré, P., Weres, J.: Inverse analysis of the transient bound water diffusion in wood. Holzforschung 59, 38–45 (2005)CrossRefGoogle Scholar
  8. Shmulsky, R., Kadir, K., Erickson, R.: Effect of air velocity on surface EMC in the drying of red oak lumber. For. Prod. J. 52, 78–80 (2002)Google Scholar
  9. Siau, J.F.: Wood: Influence of Moisture on Physical Properties. Virginia Tech, Blacksburg (1995)Google Scholar
  10. Skaar, C.: Wood-water Relations. Springer-Verlag, Berlin (1988)Google Scholar
  11. Söderström, O., Salin J. G.: On determination of surface emission factors in wood drying. Holzforschung 47, 391–397 (1993)CrossRefGoogle Scholar
  12. Stamm, A.J.: Bound water diffusion into wood in the fiber direction. For. Prod. J. 9, 27–32 (1959)Google Scholar
  13. Stamm, A. J.: Bound water diffusion into wood in the across the fiber direction. For. Prod. J. 10, 524–528 (1960)Google Scholar
  14. Wadsö, L.: Atest of different methods to evaluate the diffusivity form sorption measurements. Drying Techn. 12, 1863–1876 (1994)CrossRefGoogle Scholar
  15. Weres, J., Olek, W., Guzenda, R.: Identification of mathematical model coefficients in the analysis of the heat and mass transport in wood. Drying Technol. 18, 1697–1708 (2000)CrossRefGoogle Scholar
  16. Weres, J., Olek, W.: Inverse finite element analysis of technological processes of heat and mass transport in agricultural and forest products. Drying Technol. 23, 1737–1750 (2005)CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media B.V. 2006

Authors and Affiliations

  1. 1.Department of Mechanical Engineering and Thermal TechniquesAgricultural University of PoznańPoznańPoland
  2. 2.Institute of Agricultural EngineeringAgricultural University of PoznańPoznańPoland

Personalised recommendations