Mjerenje toplinskog kapaciteta praškastih uzoraka

master's thesis

• Title (english): Measurement of heat capacity of powder samples
• Author: Gabriela Antonije Oreški
• Mentor: Juraj Šipušić (mentor)
• Committee member: Juraj Šipušić (predsjednik povjerenstva)
• Committee member: Krunoslav Žižek (član povjerenstva)
• Committee member: Vladimir Dananić (član povjerenstva)
• Granter: University of Zagreb; Faculty of Chemical Engineering and Technology; Zagreb
• Defense date and country: 2022-09-29, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Chemical Engineering

Abstract

U ovom radu izvedena je jednostavna aparatura za mjerenje toplinskog kapaciteta praškastih nevodljivih uzoraka. Postavljena je bilanca topline ispitivanog sustava, te je odziv sustava na puls grijanja konstantnom snagom uspješno opisan kao proces prvog reda. Temperatura uzorka tijekom pulsa grijanja se mijenja, odnosno ovisi o vremenu i o prostornim koordinatama. Rješavanje ovog problema je složeno zbog komplicirane geometrije grijača i uzorka, te nepoznavanja toplinskih svojstava uzorka (praškasti i porozni materijal) koje eksperimentom zapravo treba odrediti. Promjena temperature određena je mjerenjem, te je poslužila za određivanje toplinskog kapaciteta NaCl. Određena je vrijednost toplinskog kapaciteta 24-28% veća od literaturne referentne vrijednosti, a posljedica je neuračunatih gubitaka topline u okolinu, akumulacije topline u grijaču i drugih nesavršenosti aparature.

Abstract (english)

In this work, a simple apparatus for measuring the heat capacity of powdered non-conductive samples was developed. The heat balance of the tested system was established, and the response of the system to a constant power heating pulse was successfully described as a first-order process. The temperature of the sample changes during the heating pulse, i.e. it depends on time and spatial coordinates. Solving this problem is complex due to the complicated geometry of the heater and the sample, and the lack of knowledge of the thermal properties of the sample (powder and porous material), which should actually be determined by experiment. The change in temperature was determined by measurement, and was used to determine the heat capacity of NaCl. The determined value of the heat capacity is 24-28% higher than the reference value in the literature, and it is the result of unaccounted heat losses to the environment, heat accumulation in the heater and other imperfections of the apparatus.

• Keywords: kalorimetrija; toplinski kapacitet; natrijev klorid
• Keywords (english): calorimetry; heat capacity; sodium chloride
• Language: croatian
• URN:NBN: urn:nbn:hr:149:936848
• Study programme: Title: Materials Science and Engineering - Graduate study; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra inženjer/inženjerka kemijskog inženjerstva (magistar/magistra inženjer/inženjerka kemijskog inženjerstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2023-03-29 09:28:54