prikaz prve stranice dokumenta Numerical modelling of turbulent premixed jet flames in large eddy simulation framework
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doctoral thesis
Numerical modelling of turbulent premixed jet flames in large eddy simulation framework
Zagreb: University of Zagreb, Faculty of Mechanical Engineering and Naval Architecture, 2014. urn:nbn:hr:235:777153
Perković, Luka
University of Zagreb
Faculty of Mechanical Engineering and Naval Architecture

Cite this document

Perković, L. (2014). Numerical modelling of turbulent premixed jet flames in large eddy simulation framework (Doctoral thesis). Zagreb: University of Zagreb, Faculty of Mechanical Engineering and Naval Architecture. Retrieved from https://urn.nsk.hr/urn:nbn:hr:235:777153

Perković, Luka. "Numerical modelling of turbulent premixed jet flames in large eddy simulation framework." Doctoral thesis, University of Zagreb, Faculty of Mechanical Engineering and Naval Architecture, 2014. https://urn.nsk.hr/urn:nbn:hr:235:777153

Perković, Luka. "Numerical modelling of turbulent premixed jet flames in large eddy simulation framework." Doctoral thesis, University of Zagreb, Faculty of Mechanical Engineering and Naval Architecture, 2014. https://urn.nsk.hr/urn:nbn:hr:235:777153

Perković, L. (2014). 'Numerical modelling of turbulent premixed jet flames in large eddy simulation framework', Doctoral thesis, University of Zagreb, Faculty of Mechanical Engineering and Naval Architecture, accessed 28 September 2023, https://urn.nsk.hr/urn:nbn:hr:235:777153

Perković L. Numerical modelling of turbulent premixed jet flames in large eddy simulation framework [Doctoral thesis]. Zagreb: University of Zagreb, Faculty of Mechanical Engineering and Naval Architecture; 2014 [cited 2023 September 28] Available at: https://urn.nsk.hr/urn:nbn:hr:235:777153

L. Perković, "Numerical modelling of turbulent premixed jet flames in large eddy simulation framework", Doctoral thesis, University of Zagreb, Faculty of Mechanical Engineering and Naval Architecture, Zagreb, 2014. Available at: https://urn.nsk.hr/urn:nbn:hr:235:777153

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Metadata
TitleNumerical modelling of turbulent premixed jet flames in large eddy simulation framework
Title (croatian)Numeričko modeliranje turbulentnih predmiješanih plamenova metodom simulacije velikih vrtloga
AuthorLuka Perković
MentorNeven Duić (mentor)
Committee memberŽeljko Tuković (predsjednik povjerenstva)
Committee memberNeven Duić (član povjerenstva)
Committee memberZdravko Virag (član povjerenstva)
Committee memberPeter Priesching (član povjerenstva)
strani drzavljanin: Nije dostupno
Committee memberFranjo Juretić (član povjerenstva)
GranterUniversity of Zagreb
Faculty of Mechanical Engineering and Naval Architecture
Zagreb
Defense date and country2014-06-18, Croatia
Scientific / art field,
discipline and subdiscipline		TECHNICAL SCIENCES
Mechanical Engineering
Process Energy Engineering
Universal decimal classification
(UDC)		621 - Mechanical engineering. Nuclear technology. Machinery
51 - Mathematics
004 - Computer science and technology. Computing. Data processing
Abstract
The main topic of this work's research is obtaining the methodological framework for large eddy simulation of turbulent premixed combustion. Obtaining this framework implies good knowledge of the state-of the-art in LES combustion, understanding the sub-grid scale (SGS) modelling of combustion and turbulent transport, proper definition of boundary conditions, quality mesh generation and proper numerical setup. In this work two different approaches have been used for SGS modelling of turbulent transport in Smagorinsky modelling framework. The first approach is the approach with constant value of Smagorinsky parameter. This approach is heavily relying on the chosen value of the parameter, which depends on flow configuration and simulation expertise and can introduce modelling errors if not chosen properly. Second approach is the Coherent Structure Method (CSM) approach, which is able to modify the Smagorinsky parameter according to the local coherence in the velocity field. Additionally, the CSM approach is in this work first-time used in the scope of the combustion modelling. The two approaches are mutually compared according to several criteria. The most significant comparison criteria is the comparison against available experimental data for two significantly different premixed combustion flames. The two approaches are also compared according to their level of numerical and discretization errors. Simulation results show that with the proposed methodological framework it is possible to get results which are comparable with experimental within approximately 20% of local discrepancy, with remark that CSM approach better reproduces fluctuations in the flow field. Furthermore, it is evaluated that probable cause of local discrepancy in validation comes from too excessive influence of combustion SGS modelling in regions of the flame front. This is directly related to insufficient resolution of the mesh resolution, even though the formal criteria of 80% of the resolved-to-total turbulent kinetic energy was satisfied. Conclusion is that the proposed methodological framework can be used for simulation of turbulent premixed combustion and that further improvement in result validation can be obtained by reducing the cell size in the flame region and further monitoring of numerical and discretization errors.
Abstract (croatian)
Tema ovog rada je dobivanje metodskog okvira za simulaciju turbulentnog predmiješanog plamena u okviru simulacije velikih vrtloga (eng. Large Eddy Simulation - LES). To podrazumijeva dobro poznavanje područja istraživanja vezanih uz područje simulacije velikih vrtloga, poput istraživanja vezanih uz pod-mrežne modele izgaranja i turbulentnog transporta, utjecaja definicije rubnih uvjeta kao i numeričkih postavki simulacije te utjecaj kvalitete i rezolucije računalne mreže. U ovome radu je dana usporedba dva različita pristupa računanja pod-mrežnog turbulentnog transporta u Smagorinsky-evom modelskom okviru, od kojih se jedan po prvi puta koristi za potrebe simuliranja izgaranja te su njegove implikacije na model izgaranja u ovome radu po prvi puta istražene. Prvi pristup je uobičajeni pristup u kojemu je modelski parametar Smagorinsky-evog model konstantan te ne ovisi o lokalnom toku već je uniforman u cijeloj domeni. Drugi pristup je metoda koherentnih struktura (eng. Coherent Structure Method - CSM), koji lokalno podešava parametar Smagorinsky-evog modela shodno lokalnoj koherentnosti u polju strujanja fluida. Dva pristupa su međusobno uspoređena prema nekoliko kriterija od kojih je najvažniji kriterij točnost rješenja usrednjenih i fluktuirajućih usporedbom s dostupnim eksperimentalnim podacima za dva značajno drugačija predmiješana plamena. Pristupi su također uspoređeni preko procjena grešaka diskretizacije te numeričkih grešaka. Rezultati pokazuju da je predloženim modelskim okvirima moguće dobiti zadovoljavajuća rješenja za značajno različite tipove plamena uz korištenje istih modelskih konstanti, uz napomenu da CSM pristup daje bolje rezultate fluktuirajućih veličina od pristupa sa uniformnim vrijednostima Smagorinsky-evog modelskog parametra. Nadalje, procjena je da najveći utjecaj na odstupanje od eksperimentalnih podataka uzrokuje preveliki utjecaj podmrežnog modela izgaranja, a koji je izravno vezan uz nedovoljnu rezoluciju mreže u području plamena iako je formalni kriterij od 80% izravnog rješenja u ukupnom zadovoljen za cijelu domenu. Zaključak je da predloženi modelski okvir može biti korišten u simulacijama predmiješanih turbulentnih plamenova te da se za daljnje povećanje razine točnosti rješenja predlaže korištenje finije mreže (u području plamena) od one koja je korištena u ovom radu.
Keywords
Keywords (croatian)
Languageenglish
URN:NBNurn:nbn:hr:235:777153
Study programmeTitle: 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 resourceText
File originBorn digital
Access conditionsOpen access
Terms of useLicence In copyright icon
RepositoryRepository of Faculty of Mechanical Engineering and Naval Architecture University of Zagreb
Created on2020-04-27 20:06:12

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