dc.contributor	Erhart Jiří, prof. Mgr. Ph.D. : 55025
dc.contributor.advisor	Šulc Jaroslav, doc. Ing. CSc. : 55445
dc.contributor.author	Amare, Dereje Yihun
dc.date.accessioned	2021-08-20T12:08:03Z
dc.date.available	2021-08-20T12:08:03Z
dc.date.committed	2022-4-30
dc.date.defense	2021-06-22
dc.date.submitted	2020-11-1
dc.date.updated	2021-6-22
dc.degree.level	Ing.
dc.description.abstract	The presented diploma thesis deals with the heat transfer in rectangular, horizontally oriented air enclosures. The aim of this work was to determine the effective emissivity of horizontal surfaces delimiting air enclosures with vertical walls characterized as re-emitting. Enclosures with different heights of the air layer were created in the measuring space of the measuring device HFM/436/3/1E by means of square polystyrene boards with a nominal thickness of 0.01 m, in which a coaxial square hole with a side of 0.102 m was formed. The size of the hole coincided with the size of the aerial heat flow transducers of the measuring device. The horizontal surfaces delimiting the air enclosures were formed by three materials significantly differing in their electrical resistance, on which the angular distribution of photons emitted from the surface of these materials depends. The thermal conductivity of the enclosure determined by the measurement was compared with the thermal conductivity of the enclosure calculated for the gradually increasing emissivity of the horizontal surface of the enclosure in the range of emissivity forming the surroundings of the tabulated hemispherical emissivity. When equality between measured and calculated thermal conductivities was reached, the corresponding emissivity was designated as the effective emissivity of the horizontal surfaces for a given height of the air enclosure. This solution introduces an error into the value of effective emissivity caused by the fact that the angular dependence of emissivity of real horizontal surfaces was not taken into account.	cs
dc.description.abstract	The presented diploma thesis deals with the heat transfer in rectangular, horizontally oriented air enclosures. The aim of this work was to determine the effective emissivity of horizontal surfaces delimiting air enclosures with vertical walls characterized as re-emitting. Enclosures with different heights of the air layer were created in the measuring space of the measuring device HFM/436/3/1E by means of square polystyrene boards with a nominal thickness of 0.01 m, in which a coaxial square hole with a side of 0.102 m was formed. The size of the hole coincided with the size of the aerial heat flow transducers of the measuring device. The horizontal surfaces delimiting the air enclosures were formed by three materials significantly differing in their electrical resistance, on which the angular distribution of photons emitted from the surface of these materials depends. The thermal conductivity of the enclosure determined by the measurement was compared with the thermal conductivity of the enclosure calculated for the gradually increasing emissivity of the horizontal surface of the enclosure in the range of emissivity forming the surroundings of the tabulated hemispherical emissivity. When equality between measured and calculated thermal conductivities was reached, the corresponding emissivity was designated as the effective emissivity of the horizontal surfaces for a given height of the air enclosure. This solution introduces an error into the value of effective emissivity caused by the fact that the angular dependence of emissivity of real horizontal surfaces was not taken into account.	en
dc.description.mark
dc.format	49 p. (70, 600 characters)
dc.format.extent	Ilustrace, Schémata, Grafy, Tabulky
dc.identifier.signature	V 202103216
dc.identifier.uri	https://dspace.tul.cz/handle/15240/160749
dc.language.iso	an
dc.relation.isbasedon	beginenumerate itemCengel, Y., Boles, M.A.: Heat and Mass Transfer (A Practical Approach) itemLienhard, J.H., Lienhard, J.H.: A Heat Transfer Textbook, Third ed., Philociston Press, Cambridge, Massachusetts itemAnanthasayanan, G.: Heat Transfer in Horizontally Oriented Air Enclosure, Diploma Thesis, TUL Liberec, 2020 endenumerate
dc.rights	Vysokoškolská závěrečná práce je autorské dílo chráněné dle zákona č. 121/2000 Sb., autorský zákon, ve znění pozdějších předpisů. Je možné pořizovat z něj na své náklady a pro svoji osobní potřebu výpisy, opisy a rozmnoženiny. Jeho využití musí být v souladu s autorským zákonem https://www.mkcr.cz/assets/autorske-pravo/01-3982006.pdf a citační etikou https://knihovna.tul.cz/document/26	cs
dc.rights	A university thesis is a work protected by the Copyright Act. Extracts, copies and transcripts of the thesis are allowed for personal use only and at one?s own expense. The use of thesis should be in compliance with the Copyright Act. https://www.mkcr.cz/assets/autorske-pravo/01-3982006.pdf and the citation ethics https://knihovna.tul.cz/document/26	en
dc.rights.uri	https://knihovna.tul.cz/document/26
dc.rights.uri	https://www.mkcr.cz/assets/autorske-pravo/01-3982006.pdf
dc.subject	Heat Transfer	cs
dc.subject	Conduction	cs
dc.subject	Convection	cs
dc.subject	Radiation	cs
dc.subject	Air enclosure	cs
dc.subject	Thermal conductivity	cs
dc.subject	HFM/436/3/1E Lambda	cs
dc.subject	Blackbody	cs
dc.subject	Emissivity	cs
dc.subject	View factor	cs
dc.subject	Space resistance	cs
dc.subject	Reradiating surface	cs
dc.subject	Wavelength	cs
dc.subject	Heat Transfer	en
dc.subject	Conduction	en
dc.subject	Convection	en
dc.subject	Radiation	en
dc.subject	Air enclosure	en
dc.subject	Thermal conductivity	en
dc.subject	HFM/436/3/1E Lambda	en
dc.subject	Blackbody	en
dc.subject	Emissivity	en
dc.subject	View factor	en
dc.subject	Space resistance	en
dc.subject	Reradiating surface	en
dc.subject	Wavelength	en
dc.title	Heat transfer in horizontally oriented air enclosure	cs
dc.title	Heat transfer in horizontally oriented enclosure	en
dc.type	diplomová práce	cs
local.degree.abbreviation	Navazující
local.degree.discipline	KSA
local.degree.programme	Mechanical Engineering
local.degree.programmeabbreviation	N2301
local.department.abbreviation	KEZ
local.faculty	Fakulta strojní	cs
local.faculty.abbreviation	FS
local.identifier.author	S19000341
local.identifier.stag	41785
local.identifier.verbis
local.identifier.verbis	66dcdd70-1f81-4094-bebb-fd879bf982f0
local.note.administrators	automat
local.note.secrecy	Povoleno ZverejnitPraci Povoleno ZverejnitPosudky
local.poradovecislo	3216

Heat transfer in horizontally oriented air enclosure

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