Analiza nukleacijskega vrelnega procesa v mikrogravitaciji

Berce, Jure (author), Golobič, Iztok (mentor), Zupančič, Matevž (comentor)

Proces vrenja je zaradi svoje učinkovitosti eden najbolj priljubljenih načinov prenosa toplote. Zaradi kompleksnosti procesa in velikega števila vplivnih parametrov so eksperimenti vrenja, ki so izvedeni v mikrogravitaciji, zelo ugodni, saj skoraj popolnoma izničimo vpliv težnosti, ter tako lažje preučujemo vpliv ostalih parametrov. V tem delu so predstavljeni eksperimenti vrenja, ki so bili izvedeni na Mednarodni vesoljski postaji pod pokroviteljstvom Evropske vesoljske agencije. Opisana je izvedena pretvorba surovih podatkov in strojna obdelava slik, ki je temu sledila. Popisano je nukleacijsko vrenje v treh različnih eksperimentalnih konfiguracijah v mikrogravitaciji in sicer mehurčkasto vrenje pri naravni konvekciji brez prisilnega toka tekočine, s prisilnim tokom tekočine ter mehurčkasto vrenje ob prisotnosti električnega polja. Predstavljen je vpliv posameznih procesnih parametrov na dinamiko rasti mehurčka, kot tudi vpliv obdelave slikovnih podatkov. Dobljeni rezultati so razloženi in primerjani z nekaterimi predhodnimi ugotovitvami ostalih raziskovalnih skupin. Obravnavana je ponovljivost meritev.

• Language: Slovenian
• Keywords: prenos toplote, nukleacijsko vrenje, mikrogravitacija, rast mehurčka, dinamika rasti mehurčka, strojna obdelava slik
• Work type: Master's thesis/paper
• Typology: 2.09 - Master's Thesis
• Organization: FS - Faculty of Mechanical Engineering
• Place of publishing: Ljubljana
• Publisher: [J. Berce]
• Year: 2020
• Number of pages: XXII, 59 str.
• PID: 20.500.12556/RUL-118204
• UDC: 536.24:004.946:681.518.52(043.2)
• COBISS.SI-ID: 28020483
• Publication date in RUL: 26.08.2020

Secondary language

• Language: English
• Title: Analysis of nucleate boiling process in microgravity

Abstract

Boiling is one of the most widely used methods of heat transfer, due to its high effectiveness. Because of its complexity and a high number of influential parameters the experiments conducted under microgravity conditions are favorable, as the influence of gravity can be almost completely negated. As a result, the influence of other parameters can be studied. This paper describes the boiling experiments that were conducted on the International Space Station under the patronage of the European Space Agency. Conversion of raw data and image processing is presented. Three different boiling configurations in microgravity are described and analyzed, namely nucleate boiling with natural convection without shear flow, nucleate boiling in the presence of shear flow and nucleate boiling in the presence of an electric field. The influence of experimental parameters on bubble growth dynamics and the effects of image processing is discussed. Results are explained and compared to already existing data on boiling in microgravity. Measurement repeatability is also given.

• Keywords: heat transfer, nucleate boiling, microgravity, bubble growth, bubble growth dynamics, image processing