Vizualizacija tokovnih vzorcev v kapilari hladilnega sistema

magistrsko delo magistrskega študijskega programa II. stopnje Strojništvo

Anja Kuhelj (Author), Andrej Kitanovski (Mentor), Matevž Dular (Co-mentor)

Abstract

Gospodinjski hladilnik predstavlja pomemben delež rabe energije v gospodinjstvih. Zato je ena izmed poglavitnih smernic razvoja teh naprav osredotočena na izboljšanje energijske učinkovitosti tako sistema, kot tudi posameznih komponent. Med temi je kapilarna cev eden ključnih elementov hladilnika, dobro poznavanje procesov v njej pa predstavlja temeljnji korak do njene optimizacije. V tej nalogi je predstavljena vizualizacija toka hladiva R600a skozi polimerno kapilarno cev, ki je bila nameščena v manjši parno-kompresijski sistem. Namen vizualizacije je bil opazovanje in določitev tokovnih vzorcev vzdolž kapilarne cevi ter vpliv obratovalnih pogojev nanje. Ugotovili smo, da se v kapilarni cevi pojavi več različnih tokovnih vzorcev, med katerimi prevladuje čepast tok, pri čemer se čepi raztegujejo in pospešujejo med premikanjem vzdolž toka hladiva. Spreminjanje obratovalnih pogojev je imelo velik vpliv na frekvenco nastanka mehurčkov pri uparjanju in na njihovo rast. Dodatno smo preverili še vpliv geometrijskih nepravilnosti kapilarne cevi na tokovne vzorce. Povečana hrapavost notranje površine kapilarne cevi je povzročila uparjanje na več različnih mestih hkrati, kar je povzročilo homogenizacijo dvofaznega toka.

Keywords

magistrske naloge;kapilarna cev;tokovni vzorci;uparjanje;dvofazni tok;vizualizacija;parno-kompresijski sistem;

Data

Language:	Slovenian
Year of publishing:	2020
Typology:	2.09 - Master's Thesis
Organization:	UL FS - Faculty of Mechanical Engineering
Publisher:	[A. Kuhelj]
UDC:	532.66:621.56(043.2)
COBISS:	28355587
Views:	1013
Downloads:	117
Average score:	0 (0 votes)
Metadata:

Other data

Secondary language:	English
Secondary title:	Flow pattern visualization in the capillary tube of a refrigeration system
Secondary abstract:	The household refrigerator accounts for a significant proportion of energy consumption in households. Therefore, one of the most important guidelines for the development of these appliances focuses on improving the energy efficiency of both the system and the individual components. Among these, the capillary tube is one of the key elements of the refrigerator, and a good knowledge of the processes taking place in it is a fundamental step towards its optimisation. This work presents a visualization of the flow of the refrigerant R600a through a polymer capillary tube installed in a small vapor compression system. The purpose of the visualization was to observe and determine the flow patterns along the capillary tube and the influence of the operating conditions on them. We found that several different flow patterns occur in the capillary tube, among which plug flow predominates, with the plugs expanding and accelerating as they move along the refrigerant flow. Changing operating conditions had a major impact on the frequency of bubble formation during evaporation and on their growth. We also investigated the influence of geometric irregularities of the capillary tube on the flow patterns. The increased roughness of the inner surface of the capillary tube caused evaporation at several different locations simultaneously, which led to a homogenization of the two-phase flow.
Secondary keywords:	master thesis;capillary tube;flow pattern;evaporation;two-phase flow;visualization;vapor-compression system;
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, 52 str.
ID:	12003896