Numerical simulation of metal materials quenching by applying Eulerian two-fluid model

doctoral thesis

• Title (croatian): Numerička simulacija gašenja metalnih materijala primjenom Eulerova dvofluidnoga modela
• Author: Alen Cukrov
• Mentor: Ivanka Boras (mentor)
• Committee member: Željko Tuković (predsjednik povjerenstva)
• Committee member: Yohei Sato https://orcid.org/0000-0001-5313-5767 (član povjerenstva)
• Committee member: Bojan Ničeno (član povjerenstva); VIAF: 282070885
• Committee member: Darko Landek (član povjerenstva)
• Committee member: Severino Krizmanić (član povjerenstva)
• Granter: University of Zagreb; Faculty of Mechanical Engineering and Naval Architecture; Zagreb
• Defense date and country: 2023-02-10, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Mechanical Engineering
• Universal decimal classification (UDC): 53 - Physics ; 51 - Mathematics

Abstract

A novel approach for the solution of mass transfer within the framework of the multi-fluid model supplemented with the Volume of Fluid (VOF) method, i.e. two-fluid VOF, is presented in this thesis. The governing equation set is comprised of mass, momentum, and energy conservation equations, written on a per-phase basis and supplemented with closure models via the source terms. In our method, the heat and mass transfer are calculated from the heat transfer coefficient, which has a fictitious function and depends on the local cell size and the thermal conductivity, and the implementation is straightforward because the local value is used instead of a global parameter. The interface's sharpness is ensured by the application of the geometrical reconstruction scheme implemented in VOF. The model is verified for three types of computational meshes, including triangular cells, and good agreement was obtained for the interface position and the temperature field. The straightforward application to the engineering problem of film boiling around a cylinder specimen has been carried out by supplementing the model with the prescribed turbulent kinetic energy value and, later on, in the application section, mesh motion.

Abstract (croatian)

Novi pristup za rješavanje prijenosa mase unutar okvira višefluidnoga modela potpomognutog metodom volumnog udjela fluida (engl. Volume-of-fluid, VOF), tj., dvofluidnoga VOF modela, je predstavljen u ovom radu. Skup jednadžbi održanja je sastavljen od zakona očuvanja mase, količine gibanja i energije, zapisan za svaku od faza i nadopunjen dopunskim relacijama putem izvorskih članova. U predloženoj metodi, prijenos topline i mase je računat na temelju koeficijenta prijelaza topline, koji ima fiktivnu ulogu te ovisi o lokalnoj veličini ćelije i toplinskoj provodnosti, te čija je implementacija jednostrana uslijed korištenja lokalnih vrijednosti umjesto globalnog parametra. Glatkoća, tj. oštrina granice faza je osigurana primjenom sheme geometrijske rekonstrukcije (engl. geometrical reconstruction scheme) ugrađene u VOF metodu. Model jer verificiran za tri tipa računalne (numeričke) mreže uključujući pritom i trokutne kontrolne volumene, te je postignuto zadovoljavajuće slaganje položaja granice faza i temperaturnog polja. Jednostrana primjena na inženjerski problem filmskog isparivanja oko cilindričnog uzorka jer provedena nadopunjujući model s unaprijed zadanom vrijednošću kinetičke energije turbulencije te, kasnije, u odjeljku s primjenom metode, gibajućom mrežom.

• Keywords: quenching; Stefan problem; two-fluid VOF; locally imposed closures; boiling flow; mesh versatility; frozen turbulence
• Keywords (croatian): gašenje uranjanjem; Štefanov problem; dvofluidni VOF model; lokalno narinute dopunske relacije; strujanje s isparivanjem; versatilnost numeričke mreže; zamrznuta turbulecija
• Language: english
• URN:NBN: urn:nbn:hr:235:117642
• Study programme: Title: Mechanical Engineering and Naval Architecture; Study programme type: university; Study level: postgraduate; Academic / professional title: doktor/doktorica znanosti, područje tehničkih znanosti (doktor/doktorica znanosti, područje tehničkih znanosti)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2023-02-17 13:52:52