Eksperimentalna analiza taljenja in strjevanja parafina v prozorni komori

Tkalčec, Mark (author), Šarler, Božidar (mentor), Zupančič, Matevž (comentor)

Fazno spremenljivi materiali, uporabni na številnih področjih, so pomembni zaradi sposobnosti shranjevanja in sproščanja toplote na majhnem temperaturnem intervalu. V prvem delu naloge teoretično obravnavamo fazne spremembe in lastnosti fazno spremenljivega materiala parafinskega voska. Za opazovanje taljenja in strjevanja fazno spremenljivih materialov smo zasnovali prozorno komoro, s katero lahko opazujemo trdno-kapljevite fazne prehode in merimo temperaturno polje v odvisnosti od časa. Eksperiment smo izvedli na, v okviru te zaključne naloge razviti, eksperimentalni progi, ki omogoča ločeno vzpostavitev toplega in hladnega tokokroga, pri čemer merimo pretok, temperaturo in tlak delovne tekočine (vode). V prozorno komoro smo namestili pet termočlenov in izvedli meritve temperature med taljenjem in strjevanjem v odvisnosti od časa, robnih in začetnih pogojev. Prav tako smo izmerili razliko v prostornini med kapljevito in trdno fazo parafinskega voska. Začetne in robne temperature so bile med 20 in 75 °C. Rezultati kažejo, da ima latentna toplota bistven vpliv na potek procesa strjevanja in taljenja parafinskega voska ter da je prostornina trdne faze izbranega fazno-spremenljivega materiala za približno 15 % manjša od kapljevite. Dolgotrajnost izvajanja eksperimentov (od 2 do 6 h) nakazuje potrebo po vgradnji kanalov za povečanje površine prenosa toplote, s ciljem pohitritve faznih prehodov, kar je pomembno za učinkovito uporabo.

• Language: Slovenian
• Keywords: trdno-kapljeviti sistem, taljenje, strjevanje, eksperimentalna komora, merjenje temperature, parafinski vosek
• Work type: Bachelor thesis/paper
• Organization: FS - Faculty of Mechanical Engineering
• Year: 2024
• PID: 20.500.12556/RUL-160858
• Publication date in RUL: 05.09.2024

Secondary language

• Language: English
• Title: Experimental analysis of melting and solidification of paraffin in a transparent chamber

Abstract

Phase change materials, useful in many areas, are important because of their ability to store and release heat over a small temperature interval. In the first part of the assignment, we theoretically discuss phase changes and properties of the phase-changing material paraffin wax. To observe the melting and solidification of phase-changing materials, we have designed a transparent chamber that can be used to observe solid-liquid phase transitions and measure the temperature field as a function of time. The experiment was carried out on an experimental device developed as part of this Bachelor thesis, which allows separate establishment of hot and cold circuits while measuring the flow, temperature and pressure of the working fluid (water). We installed five thermocouples in the transparent chamber and measured temperature during melting and solidification as a function of time, boundary and initial conditions. We also measured the difference in volume between the liquid and solid phases of the paraffin wax. Initial and boundary temperatures were between 20 and 75 °C. The results show that the latent heat significantly influences the course of paraffin wax's solidification and melting process and that the volume of the solid phase of the selected phase-change material is about 15 % smaller than the liquid one. The long duration of the experiments (from 2 to 6 h) indicates the need to install channels to increase the heat transfer surface, intending to accelerate phase transitions, which is essential for effective use.

• Keywords: solid-liquid system, melting, solidification, experimental chamber, temperature measurement, paraffin wax