Modelling of the 1D Convective Heat Exchange between Logs Subjected to Freezing and to Subsequent Defrosting and the Surrounding Environment
DOI:
https://doi.org/10.1515/aslh-2015-0006Keywords:
heat transfer coefficient, surface temperature, temperature distribution, beech logs, radius, hővezetési együttható, felületi hőmérséklet, hőmérsékleteloszlás, bükk rönk, sugárAbstract
A 1D mathematical model for the computation of the temperature on the surface of cylindrical logs, tsr, and the non-stationary temperature distribution along the radiuses of logs subjected to freezing and subsequent defrosting at convective exponentially changing boundary conditions has been suggested. The model includes mathematical descriptions of the thermal conductivity in radial direction, λr, the effective specific heat capacity, ce, and the density, ρ, of the non-frozen and frozen wood, and also of the heat transfer coefficient between the surrounding air environment and the radial direction of horizontally situated logs, αr. With the help of the model, computations have been carried out for the determination of αr, tsr, λsr, and 1D temperature distribution along the radiuses of beech logs with diameters of 0.24 m, initial temperature 20 ℃, and moisture content 0.4 kg*kg-1, 0.8 kg*kg–1, and 1.2 kg*kg–1, during their freezing at –20 ℃, and during subsequent thawing at 20 ℃.
References
CHUDINOV, B.S. (1966): Teoreticheskie issledovania teplofizicheskih svoystv i teplovoy obrabotki dreveciny. [Theoretical Research of Thermo-physical Properties and Thermal Treatment of Wood]. Dissertation for DSc., SibLTI, Krasnoyarsk, USSR (in Russian)
CHUDINOV, B.S. (1968): Teoria teplovoy obrabotki drevesiny [Theory of Thermal Treatment of Wood]. Nauka, Moscow, USSR, 255 p. (in Russian)
DELIISKI, N. (2004): Modelling and Automatic Control of Heat Energy Consumption Required for Thermal Treatment of Logs. Drvna Industrija, 55(4): 181–199.
DELIISKI, N. (2005) Modeling and Automatic Control of the Process of Thermal Treatment of Logs. Information Technologies and Control, UAI, Sofia, 3(2): 9–14.
DELIISKI, N. (2009): Computation of the 2-dimensional Transient Temperature Distribution and Heat Energy Consumption of Frozen and Non-frozen Logs. Wood Research, 54(3): 67−78.
DELIISKI, N. (2011): Transient Heat Conduction in Capillary Porous Bodies. In: Ahsan A. (ed): Convection and Conduction Heat Transfer. InTech Publishing House, Rijeka: 149–176, DOI: 10.5772/21424
DELIISKI, N. (2013a): Computation of the Wood Thermal Conductivity during Defrosting of the Wood. Wood research, 58(4): 637–650.
DELIISKI, N. (2013b): Modelling of the Energy Needed for Heating of Capillary Porous Bodies in Frozen and Non-frozen States. Lambert Academic Publishing, Scholars’ Press, Saarbruecken, Germany, 116 p. http://www. scholars-press.com//system/ covergenerator/build/1060
KHATTABI, A. – STEINHAGEN, H. P. (1992): Numerical Solution to Two-dimensional Heating of Logs. Holz als Roh- und Werkstoff, 50(7–8): 308–312, DOI: 10.1007/BF02615359
KHATTABI, A. – STEINHAGEN, H. P. (1993): Analysis of Transient Non-linear Heat Conduction in Wood Using Finite-difference Solutions. Holz als Roh- und Werkstoff, 51(4): 272–278, DOI: 10.1007/BF02629373
KHATTABI, A. – STEINHAGEN, H. P. (1995): Update of “Numerical Solution to Two-dimensional Heating of Logs”. Holz als Roh- und Werkstoff, 53(1): 93–94, DOI: 101007/BF02716399
NIKOLOV, S. – VIDELOV, C. (1987): Spravochnik za sushene na darvesinata [Handbook for Wood Drying]. Zemizdat, Sofia, 394 p. (in Bulgarian)
POŽGAJ, A. – CHOVANEC, D. – KURJATKO, S. – BABIAK, M. (1997): Štruktúra a vlastnosti dreva [Structure and properties of wood]. 2nd edition, Priroda a.s., Bratislava, 485 p. (in Slovak)
SERGOVSKY, P. S. (1975): Gidrotermicheskaya obrabotka i konservirovanie drevesiny [Hydro-thermal Treatment and Conserving of Wood]. Lesnaya Promyshlennost, Moskow, URSS, 400 p. (in Russian)
SHUBIN, G. S. (1990): Sushka i teplovaya obrabotka drevesiny [Drying and Thermal Treatment of Wood]. Lesnaya Promyshlennost, Moskow, USSR, 337 p. (in Russian)
STEINHAGEN, H. P. (1986): Computerized Finite-difference Method to Calculate Transient Heat Conduction with Thawing. Wood Fiber Science, 18(3): 460–467.
STEINHAGEN, H. P. (1991): Heat Transfer Computation for a Long, Frozen Log Heated in Agitated Water or Steam – A Practical Recipe. Holz als Roh- und Werkstoff, 49(7–8): 287–290, DOI: 10.1007/BF02663790
STEINHAGEN, H. P. – LEE, H. W. (1988): Enthalpy Method to Compute Radial Heating and Thawing of Logs. Wood Fiber Science, 20(4): 415–421.
STEINHAGEN, H. P. – LEE, H. P. – LOEHNERTZ, S. P. (1987): LOGHEAT: A Computer Program of Determining Log Heating Times for Frozen and Non-Frozen Logs. Forest Products Journal, 37(11–12): 60–64.
TREBULA, P. – KLEMENT, I. (2002): Drying and Hydro-thermal Treatment of Wood. Technical University in Zvolen, Slovakia, 449 p. (in Slovak)
VIDELOV, CH. (2003): Sushene i toplinno obrabotvane na darvesinata [Drying and Thermal Treatment of Wood]. University of Forestry in Sofia, Sofia, 335 p. (in Bulgarian)
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