IR termografska analiza vrenja v bazenu na vertikalno orientiranih kovinskih folijah

magistrsko delo magistrskega študijskega programa II. stopnje Strojništvo

Jaka Jernejc (Author), Matic Može (Mentor), Iztok Golobič (Co-mentor)

Abstract

Vrenje je eden najučinkovitejših načinov prenosa toplote, ki pri majhnih temperaturnih razlikah omogoča odvod velikih gostot toplotnega toka. Proces nukleacije predstavlja ključen fenomen pri tem mehanizmu prenosa toplote, zato je pomembno poznavanje in razumevanje faktorjev, ki vplivajo na nukleacijo. Magistrsko delo obravnava proces vrenja v bazenu na vertikalno orientiranih površinah iz nerjavnega jekla z uporabo IR termografske analize. Na površinah smo z laserskim teksturiranjem in uporabo hidrofobnega premaza izdelali vzorce s hidrofilnim, hidrofobnim nukleacijskim mestom in enega s tremi hidrofilnimi nukleacijskimi mesti. Ob uporabi eksperimentalne proge smo za tri vzorce opravili meritve pri treh različnih podhladitvah vode – 1, 4 in 9 K pri izpostavljenosti vzorca gostotam toplotnega toka med 70 in 130 kW m-2. Ugotovili smo, da se lokalne temperature vrelne površine in gostote toplotnega toka na mestu nukleacije, pri zmanjšanju podhladitve in povečanju gostote toplotnega toka, ki mu je vzorec izpostavljen povečujejo, hkrati pa se povečuje tudi premer nastalih mehurčkov.

Keywords

magistrske naloge;vrenje v bazenu;gostota;toplotni tok;premer mehurčka;podhlajeno vrenje;IR termografska analiza;nukleacija;

Data

Language:	Slovenian
Year of publishing:	2023
Typology:	2.09 - Master's Thesis
Organization:	UL FS - Faculty of Mechanical Engineering
Publisher:	[J. jernejc]
UDC:	536.2:66.046.7(043.2)
COBISS:	142997251
Views:	295
Downloads:	35
Average score:	0 (0 votes)
Metadata:

Other data

Secondary language:	English
Secondary title:	IR thermographic investigation of pool boiling process on vertically oriented metal foils
Secondary abstract:	Boiling is considered as one of the processes with the most effective heat removal. It enables high heat fluxes at relatively low temperature differences. Bubble nucleation reperesents the key mechanism of the process; therefore, it is vital to be familiar with factors that influence nucleate boiling process and understand them. This thesis investigates the pool boiling process on vertically oriented, stainless steel surfaces, using IR thermographic analysis. Laser texturing and the hydrophobic coating was used to fabricate three samples – one with hydrophilic, one with hydrophobic nucleation spot and one with three hydrophilic spots. Using an experimental setup, we performed measurements on samples for three different subcooling, of water bulk – 1, 4, and 9 K. The sample was exposed to heat fluxes between 70 and 130 kW m-2.. We found that local boiling surface temperatures and heat fluxes increase with the decrease of subcooling and the increase of the heat flux that the sample is exposed to. At the same time, with the increase of subcooling and decrease of exposure heat flux, bubble diameters are reduced.
Secondary keywords:	master thesis;pool boiling;heat flux;bubble diameter;subcooled boiling;IR thermographic analysis;nucleation;
Type (COBISS):	Master's thesis/paper
Study programme:	0
Thesis comment:	Univ. Ljubljana, Fak. za strojništvo
Pages:	XX, 60 str.
ID:	18085015