zaključna naloga Univerzitetnega študijskega programa I. stopnje Strojništvo - Razvojno raziskovalni program
Matevž Vodopivec (Author), Iztok Golobič (Mentor), Matevž Zupančič (Co-mentor)

Abstract

Mehurčkasto vrenje je eden izmed najučinkovitejših mehanizmov prenosa toplote in je široko raziskovano na področjih, kjer se zahteva visoka odvedena gostota toplotnega toka pri nizkih pregretjih površine. V tem delu smo eksperimentalno ovrednotili proces vrenja vode na tankih kovinskih folijah z nanosom grafenskega oksida ter na folijah z lasersko strukturiranim nukleacijskim mestom z in brez grafenskega oksida pri treh različnih gostotah toplotnih tokov. Iz meritev s hitrotekočo infrardečo kamero smo pridobili podatke o nestacionarnih temperaturnih poljih na površini, porazdelitvi gostote toplotnega toka in koeficientih toplotne prestopnosti, lokaciji nukleacijskih mest in frekvencah nukleacij. Izvedli smo tudi analizo omočljivosti površin, s hitrotekočo videokamero pa smo pridobili posnetke rasti vrelnih mehurčkov. Nanos grafenskega oksida je zagotovil večje število aktivnih nukleacijskih mest, hkrati pa je povzročil povišanje temperature nukleacije in ni zagotovil bolj homogene temperaturne porazdelitve. Lasersko ustvarjeno nukleacijsko mesto je omogočilo analizo izoliranega parnega mehurčka, ki je potrdila, da zahteva grafenski oksid višje pregretje za pojav nukleacije. Rezultati dela odpirajo možnosti nadaljnjih raziskav izoliranih nukleacij parnih mehurčkov in velikosti aktivnih nukleacijskih mest, smiselno pa bi bilo raziskati tudi vpliv grafenskega oksida na vrenje dielektričnih fluidov.

Keywords

diplomske naloge;mehurčkasto vrenje;grafenski oksid;nukleacijska mesta;gostota toplotnega toka;vrenje v bazenu;omočljivost;

Data

Language: Slovenian
Year of publishing:
Typology: 2.11 - Undergraduate Thesis
Organization: UL FS - Faculty of Mechanical Engineering
Publisher: [M. Vodopivec]
UDC: 536.24:53.08(043.2)
COBISS: 111216899 Link will open in a new window
Views: 158
Downloads: 69
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Other data

Secondary language: English
Secondary title: Experimental analysis of nucleate pool boiling on thin metal foils with graphene oxide deposit
Secondary abstract: Nucleate boiling is one of the most efficient mechanisms of heat transfer and it is extensively researched in areas where high heat flux at low wall superheat is needed. In this thesis, we experimentally evaluated the boiling process of water on thin metal foils with and without a laser textured nucleation spot at three different heat fluxes. Graphene oxide deposition was used on both types of foils. High-speed IR camera was used to obtain temperature field data, heat flux and heat transfer coefficient distributions, active nucleation site locations and nucleation frequency. Surface wettability analysis was also carried out and a high-speed video camera was used to record bubble growth. Graphene oxide deposition caused an increase in the amount of active nucleation sites, however, it also increased nucleation temperature and it did not ensure a more homogeneous temperate distribution. Laser textured nucleation spot enabled analysis of an isolated bubble, which confirmed that higher wall superheat is needed for nucleation with graphene oxide deposition. The results open possibilities of future research on isolated vapor bubble nucleation and active nucleation site sizes, while it would also be beneficial to explore the effect of graphene oxide deposition on boiling of dielectric fluids.
Secondary keywords: thesis;nucleate boiling;graphene oxide;nucleation spot;heat flux;pool boiling;wettability;
Type (COBISS): Final paper
Study programme: 0
Thesis comment: Univ. v Ljubljani, Fak. za strojništvo
Pages: XV, 66 f.
ID: 15595291