20.500.12556/RUL-136595 Vpliv hitrosti gibanja zraka na kinetiko konvekcijskega sušenja bukovine (Fagus sylvatica L.) Influence of air velocity on kinetics of kiln drying of beechwood (Fagus sylvatica L.) Raziskava primarno proučuje kinetiko konvekcijskega sušenja bukovine (Fagus sylvatica L.) v svežem stanju ter učinke procesnih pogojev v nadaljevanju sušilnega procesa. Uporabili smo sveže radialno orientirane preizkušance, debeline od 6 mm do 24 mm (ΔL = 6 mm). Enosmerno konvekcijsko sušenje smo izvedli pri konstantni temperaturi 30 °C in 85 % relativni zračni vlažnosti z variiranjem hitrosti gibanja zraka od 0,6 m/s do 7,6 m/s. Med procesom smo gravimetrično določali lesno vlažnost in vlažnostni gradient. Sušilna hitrost je v svežem stanju lesa splošno naraščala s povečevanjem hitrosti gibanja zraka. V začetnem stanju je v kratkem intervalu faza relativno konstantne sušilne hitrosti dosežena le pri tanjših preizkušancih (≤ 12 mm) pri hitrostih gibanja zraka do 2,5 m/s. Višja hitrost gibanja zraka (> 2,5 m/s) pri sušenju lesa v svežem stanju sicer poveča masni tok vode, a hkrati povzroči velik podpovršinski vlažnostni gradient. Posledično kinetiko sušenja v nadaljevanju determinira značilen notranji difuzijski upor, kar bistveno podaljša celotni proces For determination of suitable process conditions at drying of European beechwood (Fagus sylvatica L.) the unidirectional drying kinetics, with an emphasis of free water removal was researched. We used radially oriented sapwood specimens, having thickness from 6 mm to 24 mm (ΔL = 6 mm). Series of conventional drying processes were carried out in the laboratory tunnel drier at constant climate (T = 30 °C, φ = 85 %) with various air velocities from 0.6 m/s to 7.6 m/s. During the drying, moisture content, moisture gradient and moisture flow were gravimetrically determined at successive time intervals. Drying rate generally increased by rising of the air velocity and decreased by increasing of wood thickness. Relatively constant drying rate was present at thinner specimens (≤ 12 mm) in a short time interval of the initial stage of the process, when low air velocity was used (≤ 2.5 m/s). Increasing of the air velocity (> 2.5 m/s) lead to early irreversible reduction of initial moisture flow and to the transition into the period of significantly falling drying rate, where the internal mass resistance predominated. The diffusion barrier was induced at too fast free water removal which controlled further drying rate and significantly prolonged the process in continuation les sušenje hitrost gibanja zraka masni tok vode vlažnostni gradient wood drying air velocity water mass flow moisture gradient true false true Slovenski jezik Angleški jezik Članek v reviji 2022-05-12 09:55:20 2022-05-12 09:55:21 2022-09-15 04:14:03 0000-00-00 00:00:00 2011 0 0 Str. 317-322 št. 8/9 Letn. 63 2011 0000-00-00 Zaloznikova Objavljeno NiDoloceno 0000-00-00 0000-00-00 2011-01-01 630*847 0024-1067 1965961 RAZ_Straze_Ales_2011.pdf RAZ_Straze_Ales_2011.pdf 1 42707DE1C113083669D719CDC7B87B43 e5beb778d3a85f31c2c66d74a9cb0842663957a7e8ada0caf450fb6f5d5a739f 98883a88-d1c9-11ec-8aca-00155dcfd717 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=156305 Biotehniška fakulteta Les 0 0 0