Vpliv ostrine sušenja na generiranje notranjih napetosti

diplomsko delo - visokošolski strokovni študij

Andrej Romšak (Author), Primož Oven (Reviewer), Željko Gorišek (Mentor)

Abstract

Bukev je naša najpomembnejša domača listnata lesna vrsta. Med sušenjem je bukovina zelo nagnjena k pokanju, veženju in obarvanosti, kar zahteva skrben pristop k načrtovanju in izvajanju sušilnega postopka. Na 25 mm in 50 mm debelih žaganih elementih, ki smo jih sušili z 2 ostrinama sušenja, smo intervalno, pri vsakem padcu vlažnosti za pribl. 5 %, določali povprečno vlažnost, vlažnostni gradient in sušilne napetosti. Ostrejši režim je vplival na večjo sušilno hitrost, predvsem pri sušenju pod točko nasičenja celičnih sten. Hitrost sušenja tangencialno orientiranih vzorcev je bila večja (0,064 %/h) od hitrosti sušenja radialnih (0,05 %/h). Prav tako so se v tangencialnih elementih generirale večje sušilne napetosti. Kritična faza sušenja z največjimi sušilnimi napetostmi je pri povprečni vlažnosti 15-20 %. Vlažnostni gradient je v radialnih elementih (2,36 %/cm) nekoliko večji kot v tangencialnih (1,82 %/cm).

Keywords

les;bukovina (Fagus sylvatica L.);sušenje;vlažnostni gradient;zaskorjenje;sušilne napetosti;kakovost;

Data

Language:	Slovenian
Year of publishing:	2016
Typology:	2.11 - Undergraduate Thesis
Organization:	UL BF - Biotechnical Faculty
Publisher:	[A. Romšak]
UDC:	630*847
COBISS:	2677129
Views:	285
Downloads:	70
Average score:	0 (0 votes)
Metadata:

Other data

Secondary language:	English
Secondary title:	Influence of drying conditions on stress development
Secondary abstract:	Beech wood is the most important Slovenian hardwood. During drying process its tendency to cracking and banding demands carefully planning and performing drying programme. In experiment, 25 mm and 50 mm thick boards were included, which were dried in 2 different drying conditions. Control samples for moisture, moisture gradient and drying stresses were taken frequently, every time when moisture in boards fell down for about 5 %. The influence of sharper drying conditions on drying speed was indicative when moisture fell under fibre saturation point (FSP). The drying speed in tangential samples (0.064 %/h) was higher than in radial samples (0.05 %/h). Drying stresses were also higher in tangential samples. Critical phase in the drying process with highest drying stresses was 15-20 % at average moisture. Moisture gradient was a little higher in radial samples (2.36 %/cm) than in tangential samples (1.82 %/cm).
Secondary keywords:	wood;beech (Fagus sylvatica L.);drying;moisture gradient;casehardening;drying stress;quality;
Type (COBISS):	Undergraduate thesis
Thesis comment:	Univ. v Ljubljani, Biotehniška fak., Oddelek za lesarstvo
Pages:	XII, 41 f., [6] f. pril.
ID:	11928325