Gustoća pakiranja polidisperznih čestica

master's thesis

• Title (english): Polydisperse particle packing density
• Author: Antonio Kapusta
• Mentor: Juraj Šipušić (mentor)
• Committee member: Juraj Šipušić (predsjednik povjerenstva)
• Committee member: Jelena Macan (član povjerenstva)
• Committee member: Andrej Vidak (član povjerenstva)
• Granter: University of Zagreb; Faculty of Chemical Engineering and Technology; Zagreb
• Defense date and country: 2021-07-15, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Chemical Engineering

Abstract

Pretpostavljeno je da kružna frekvencija titranja fizičkog njihala (posude za praškasti uzorak) ovisi o gustoći pakiranja ispitivanih polidisperznih čestica. U ovome radu sastavljena je aparatura za praćenje titranja fizičkog njihala. Aparatura omogućuje određivanje elongacije prigušenog titranja posude (sa ili bez uzorka), iz koje se određuje kružna frekvencija titranja. Izvedba aparature omogućuje mjerenje titranja oko više paralelnih osi titranja međusobno udaljenih za poznati razmak od 0.025 m. Maksimalno je smanjen utjecaj trenja između osi titranja i fizičkog njihala (posude s uzorkom), ali je mjerenje i dalje osjetljivo na vanjske smetnje poput vibracija poda i fluktuacija u strujanju zraka. Upravo ti problemi otvaraju mogućnost unaprjeđenja postojeće aparature. Udaljenost određene osi rotacije od težišta prazne posude, odnosno moment inercije prazne posude kroz os rotacije koja prolazi njenim težištem određeni su mjerenjem titranja prazne posude oko više paralelnih osi rotacije koje su međusobno udaljene za poznati razmak od 0.025 m. Dobiveni rezultati pokazuju rasipanje pa su izraženi kao srednja vrijednost svih mjerenja. Određena je udaljenost najudaljenije osi titranja od težišta posude od 0.10925 m i moment inercije prazne posude oko osi rotacije koja prolazi kroz njeno težište koji iznosi 4.35*10^-4 kgm^2. Eksperimentalna ovisnost kružne frekvencije o masi uzorka se kvalitativno slaže s matematičkim modelom, ali ne i kvantitativno. Za bolje slaganje je potrebno modificirati aparaturu i/ili unaprijediti matematički model.

Abstract (english)

For the purpose of this thesis, it was assumed that the angular frequency of a real oscillator (a container for granular particles) depends on the density of packing of the measured polydisperse particles. In this thesis, an apparatus for the monitoring of real oscillators was made. This apparatus enables measurement of the elongation of damped oscillation of the container (with or without the sampe) from which is the angular frequency determined. The apparatus was constructed in such a manner that it allows measurement of damped oscillation about multiple parallel axes which are mutually spaced for a predetermined gap of 0.025 m. The influence of friction (between the container the the rotation axes) was maximally reduced, yet the measurements were still highly sensitive to disturbances from the surrounding like vibrations and fluctuations in the air's movement. These problems open up possibilities for further enhancements of the apparatus. The distance between a specific rotation axis and the container's central diameter and the container's central diameter moment of inertia were determined through the measurement of the container's oscillation about several parallel axes which are spaced for 0.025 m. The results were dissipated, therefore they were interpreted as the mean value. The distance between the furthest rotation axis and the container's central diameter is 0.10925 m and the container's central diameter moment of inertia is 4.35*10^-4 kgm^2. A constructed curve depicting experimentally gained data qualitatively matches the curve that was constructed from the mathematical model, but not quantitatively. Apparatus and mathematical model improvements are needed for further experiments.

• Keywords: gustoća polidisperznih čestica; moment inercije; titranje
• Keywords (english): density of polydisperse particles; moment of inertia; oscillation
• Language: croatian
• URN:NBN: urn:nbn:hr:149:178930
• 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: 2023-04-11 08:45:32