Title
Eksperimentalno i numeričko istraživanje termo-strujnih procesa u spiralnom naboranom toplotnom apsorberu koncentrisanog zračenja
Creator
Đorđević, Milan LJ.
Copyright date
2016
Object Links
Select license
Autorstvo-Nekomercijalno-Bez prerade 3.0 Srbija (CC BY-NC-ND 3.0)
License description
Dozvoljavate samo preuzimanje i distribuciju dela, ako/dok se pravilno naznačava ime autora, bez ikakvih promena dela i bez prava komercijalnog korišćenja dela. Ova licenca je najstroža CC licenca. Osnovni opis Licence: http://creativecommons.org/licenses/by-nc-nd/3.0/rs/deed.sr_LATN. Sadržaj ugovora u celini: http://creativecommons.org/licenses/by-nc-nd/3.0/rs/legalcode.sr-Latn
Language
Serbian
Cobiss-ID
Theses Type
Doktorska disertacija
description
Datum odbrane: 23.11.2016.
Other responsibilities
mentor
Stefanović, Velimir
član komisije
Lukić, Nebojša 1964-
član komisije
Vukić, Mića 1965-
član komisije
Kalaba, Dragan
Academic Expertise
Tehničko-tehnološke nauke
University
Univerzitet u Nišu
Faculty
Mašinski fakultet
Group
Katedra za termotehniku, termoenergetiku i procesnu tehniku
Alternative title
Experimental and numerical investigation of thermal-hydraulic processes in spirally coiled corrugated tubes of heat absorber exposed to concentrated radiant energy
Publisher
[М. Lj. Đorđević]
Format
VIII, 218 str.
description
Thermotechnics, Thermoenergetics and Process Engineering
Abstract (en)
The utilization of modern paraboloidal concentrators for conversion of solar radiation into heat energy requires the development and implementation of compact and efficient heat absorbers. This research is directed toward innovative design solution that involves the development of heat absorber made of spirally coiled tubes with transverse circular corrugations. The main advantage of the considered design solution is a coupling effect of the two passive methods for heat transfer enhancement - coiling of the flow channel and changes in surface roughness. Investigation of the influence of hydraulic, physical and thermal conditions, as well as the geometry of the spirally coiled corrugated heat absorber, on the local intensity of heat transfer and pressure drop was conducted using modern experimental and numerical methods. Laboratory model of heat absorber was instrumented and mounted in the radiation field. Test section instrumentation included inlet fluid flow rate, pressure drop, inlet and exit fluid temperature and 35 type K thermocouples welded to the surface of the coil. The thermal analysis of experimentally obtained data included consideration of the externally applied radiation field, convective and radiative heat losses, conduction through the tube wall and convection to the internal fluid. The experimental results showed significant enhancement of the heat transfer compared to spirally coilled smooth tubes, up to 240% in the turbulent flow regime. The influence of radiant field intensity and geometrical parameters of corrugations outside the experimental range were investigated using computational fluid dynamics techniques in terms of heat transfer and pressure drop. Finally, the reliable correlations for determining the intensity of convective heat transfer coefficient and pressure drop were obtained for different flow regimes, which are applicable in engineering practice.
Authors Key words
toplotni apsorber, spiralna cev sa poprečnim naborima, termo-strujni procesi
Authors Key words
Heat Absorber, Spirally Coiled Tubes with Transverse Corrugations, Thermal-hydraulic Processes
Classification
66.045.1+621.643.1-023.737(043.3)
Subject
536.2/.7+532.5]:519.6(043.3)
Subject
T 200
Type
Elektronska teza
Abstract (en)
The utilization of modern paraboloidal concentrators for conversion of solar radiation into heat energy requires the development and implementation of compact and efficient heat absorbers. This research is directed toward innovative design solution that involves the development of heat absorber made of spirally coiled tubes with transverse circular corrugations. The main advantage of the considered design solution is a coupling effect of the two passive methods for heat transfer enhancement - coiling of the flow channel and changes in surface roughness. Investigation of the influence of hydraulic, physical and thermal conditions, as well as the geometry of the spirally coiled corrugated heat absorber, on the local intensity of heat transfer and pressure drop was conducted using modern experimental and numerical methods. Laboratory model of heat absorber was instrumented and mounted in the radiation field. Test section instrumentation included inlet fluid flow rate, pressure drop, inlet and exit fluid temperature and 35 type K thermocouples welded to the surface of the coil. The thermal analysis of experimentally obtained data included consideration of the externally applied radiation field, convective and radiative heat losses, conduction through the tube wall and convection to the internal fluid. The experimental results showed significant enhancement of the heat transfer compared to spirally coilled smooth tubes, up to 240% in the turbulent flow regime. The influence of radiant field intensity and geometrical parameters of corrugations outside the experimental range were investigated using computational fluid dynamics techniques in terms of heat transfer and pressure drop. Finally, the reliable correlations for determining the intensity of convective heat transfer coefficient and pressure drop were obtained for different flow regimes, which are applicable in engineering practice.
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