Hidrofobne in hidrofilne bakrene površine za izboljšan prenos toplote pri mehurčkastem vrenju vode

magistrsko delo magistrskega študijskega programa II. stopnje Strojništvo

David Koplan (Author), Iztok Golobič (Mentor), Matic Može (Co-mentor)

Abstract

V magistrski nalogi smo raziskali uporabo hidrofobnih in hidrofilnih lasersko strukturiranih površin za izboljšanje prenosa toplote pri mehurčkastem vrenju vode. Na površinah smo z uporabo vlakenskega bliskovnega laserja pripravili različne mikrostrukture, s hidrofobizacijo izbranih vzorcev smo zasledovali dodatno znižanje pregretja površine. Pokazali smo, da na vseh funkcionaliziranih površinah zabeležimo izboljšanje intenzivnosti prenosa toplote pri vrenju, kar se odrazi v dvigu kritične gostote toplotnega toka in povečanju koeficienta toplotne prestopnosti. Dodatno smo zabeležili zgodnejši prehod v režim mehurčkastega vrenja, kar je bilo izrazito predvsem na hidrofobiziranih površinah. Dosegli smo koeficiente toplotne prestopnosti do 287 kW/m2K, kar pomeni 9-kratno izboljšanje v primerjavi z neobdelano površino. Najvišja kritična gostota toplotnega toka je znašala 1660 kW/m2, kar predstavlja 83 % izboljšanje v primerjavi z neobdelano površino. Z razvitimi površinami bi lahko pomembno izboljšali intenzivnost odvoda toplote v aplikacijah, kjer nastopajo koncentrirane toplotne obremenitve zaradi generacije toplote na majhnih površinah.

Keywords

magistrske naloge;mehurčkasto vrenje;prenos toplote;lasersko obdelane površine;vrenje v bazenu;koeficient toplotne prestopnosti;

Data

Language:	Slovenian
Year of publishing:	2022
Typology:	2.09 - Master's Thesis
Organization:	UL FS - Faculty of Mechanical Engineering
Publisher:	[D. Koplan]
UDC:	536.24:66.046.7:532(043.2)
COBISS:	107055107
Views:	146
Downloads:	41
Average score:	0 (0 votes)
Metadata:

Other data

Secondary language:	English
Secondary title:	Hydrophobic and hydrophilic copper surfaces for enhanced nucleate boiling heat transfer with water
Secondary abstract:	In this master's thesis, we have researched the use of hydrophobic and hydrophilic laser structured surfaces for enhanced boiling heat transfer. We fabricated different surface microstructures using a pulsed fiber laser combined with selective hydrophobization to pursue an additional decrease in wall superheat. All functionalized surfaces exhibited increased heat transfer intensity under pool boiling conditions through increased critical heat flux and higher heat transfer coefficients. Additionally, an earlier onset of nucleate boiling was observed, which was especially true for hydrophobic surfaces. We achieved heat transfer coefficients of up to 287 kW/m2K, which is a 9x improvement in comparison with an untreated reference surface. The highest measured critical heat flux was 1660 kW/m2, which represents an 83 % increase with respect to the treated surface. With developed surfaces, it is possible to substantially increase the intensity of heat transfer in applications, where heat loads are highly concentrated.
Secondary keywords:	master thesis;heat transfer;nucleate boiling;laser surface texturing;
Type (COBISS):	Master's thesis/paper
Study programme:	0
Embargo end date (OpenAIRE):	1970-01-01
Thesis comment:	Univ. Ljubljana, Fak. za strojništvo
Pages:	XXII, 65 str.
ID:	15229743