Abstract
In transport models for wood, sorption is an essential parameter. Sorption is the balancing process between the two phases of water present in wood below the fiber saturation point, namely water vapor in the lumens and bound water in the cell walls. To gain better insight into the physical background of transport processes, a special experimental test setup—the improved cup method—is presented. It allows for separation of sorption from other processes. In this test, a diffusion cup contains a thin specimen of wood, with one side facing outwards to a climate chamber and the opposite side facing inwards the cup. In contrast to the common cup method, the herein presented method uses a data logger for relative humidity and temperature placed inside the cup. The use of thin cross-cut specimens allows for explicit separation of the different processes occurring during transient moisture transport. Mass changes were determined and relative humidity inside the cups was measured for eight specimens of Norway spruce with different specimen thicknesses. Relative humidity was increased in three uniform steps in the test chamber from 4.0 up to 76.5%. The results obtained with this special test setup indicate that the sorption process is different than assumed in previous publications. This emphasizes the need of improved modeling approaches.
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References
Absetz, I.: Moisture transport and sorption in wood and plywood—theoretical and experimental analysis originating from wood cellular structure. PhD thesis, Helsinki University of Technology (1999)
Comstock G.L.: Moisture diffusion coefficients in wood as calculated from adsorption, desorption, and steady state data. For. Prod. J. 13, 97–103 (1963)
Crank J.: The Mathematics of Diffusion. 2nd edn. Oxford University Press, Oxford (1975)
Eitelberger J., Hofstetter K.: Prediction of transport properties of wood below the fiber saturation point—a multiscale homogenization approach and its experimental validation. Part II: steady state moisture diffusion coefficient. Comp. Sci. Technol. 71, 145–151 (2011a)
Eitelberger J., Svensson S., Hofstetter K.: Theory of transport processes in wood below the fiber saturation point. Physical background on the microscale and its macroscopic description. Holzforschung 65, 337–342 (2011b)
Eitelberger J., Hofstetter K.: A comprehensive model for transient moisture transport in wood below the fiber saturation point: physical background, implementation and experimental validation. Int. J. Therm. Sci. 50, 1861–1866 (2011c)
Eitelberger, J., Hofstetter, K., Dvinskikh, S.: A multi-scale approach for simulation of transient moisture transport processes in wood below the fiber saturation point. Comp. Sci. Technol. (2011d) 71, 1727–1738
Frandsen H.L.: Modeling of moisture transport in wood, state of the art and analytic discussion. Techical reports, Department of Building Technology and Structural Engineering, Aalborg University, Aalborg (2005)
Frandsen H.L., Damkilde L., Svensson S.: A revised multi-fickian moisture transport model to describe non-fickian effects in wood. Holzforschung 61, 563–572 (2007)
Grigull U., Straub J., Schiebener P.: Steam Tables in SI-Units. 3rd edn. Springer, New York, Berlin, Heidelberg (1990)
Hailwood, A.J., Horrobin, S.: Absorption of water by polymers. Analysis in terms of a simple model. Trans. Faraday Soc. 42B, 84–92, 94–102 (1946)
Hozjan T., Svensson S.: Theoretical analysis of moisture transport in wood as an open porous hygroscopic material. Holzforschung 65, 97–102 (2011)
Krabbenhoft K., Damkilde L.: A model for non-Fickian moisture transfer in wood. Mater. Struct. 37, 615–622 (2004)
Siau J.F.: Transport Processes in Wood. Springer, Berlin, Heidelberg, New York (1984)
Skaar C.: Wood–Water Relations. Springer, Berlin, Heidelberg, New York (1988)
Wadsö L.: Measurements of water vapour sorption in wood, part 1. Instrumentation. Wood Sci. Technol. 27, 396–400 (1993a)
Wadsö L.: Measurements of water vapour sorption in wood, part 2. Results. Wood Sci. Technol. 28, 59–65 (1993b)
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Eitelberger, J., Svensson, S. The Sorption Behavior of Wood Studied by Means of an Improved Cup Method. Transp Porous Med 92, 321–335 (2012). https://doi.org/10.1007/s11242-011-9905-8
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DOI: https://doi.org/10.1007/s11242-011-9905-8