Uticaj različitog sadržaja vlage na termalna svojstva drva

Petr Kotoulek,Martin Malínek,Monika Božiková,Peter Hlaváč,Matúš Bilčík,Ana Petrović,Ján Csillag

doi:10.5937/jpea1901024k

Abstract

Moisture content is one of the most important properties of wood. The primary purpose of this paper is to examine the dependence between thermal properties and different moisture contents of softwood, hardwood and medium hardwood samples with dimensions of 100 x 100 mm and a thickness of 10 mm (measured using the transient method). Different moisture contents of the wood samples under consideration were achieved by a gradual drying treatment in the laboratory setting. The final results obtained represent the arithmetic means computed from ten sets of measurements. The measured relationship between the thermal conductivity and the mass specific heat of the wood samples was found to indicate an increasing trend, whereas the relationship between the thermal diffusivity and the moisture content of the wood samples showed a non-linear decreasing trend. On the basis of the results obtained, it can be concluded that the thermal properties of wood are greatly affected by the type of wood and changes in the wood moisture content, which mainly depend on wood structure and water conduction in wood.

Highlights

Thermal properties of wood are of immense importance to fuel conversion, building construction and other types of industry (Zi-Tao et al 2011)
The heat conductivity of wood depends on the following factors affecting the rate of heat flow in wood: density, moisture content, direction of heat flow, and distribution of chemical substances in wood (Ružiak et al, 2017)
Thermophysical property measurements were performed on three different types of wood samples: softwood – spruce (Picea abies), hardwood – beech (Fagus sylvatica) and medium hardwood – chestnut (Aesculus hippocastanum)

Summary

Introduction

Thermal properties of wood are of immense importance to fuel conversion, building construction and other types of industry (Zi-Tao et al 2011). Transient simultaneous measurements of the thermal conductivity and diffusivity of Swedish wood have been performed using the plane source technique on oven-dry hardwood – birch (Betula) samples by Suleiman et al (1999). The specific heat capacity of the selected types of wood was examined relative to the temperature and moisture content (Radmanović et al, 2014). Measurements of the thermophysical properties of the wood samples analysed, i.e. the thermal conductivity, thermal diffusivity and dependence between the mass specific heat and different moisture contents, were performed in the present study

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