New physically based sub-models for the cycle-simulation of spark-ignition engine

doctoral thesis

• Title (croatian): Novi fizikalni pod-modeli simulacije radnog ciklusa Ottovog motora
• Author: Momir Sjerić
• Mentor: Darko Kozarac (mentor)
• Committee member: Zoran Lulić (predsjednik povjerenstva)
• Committee member: Darko Kozarac (član povjerenstva)
• Committee member: Neven Duić (član povjerenstva)
• Committee member: Daniel Rolph Schneider (član povjerenstva)
• Committee member: Reinhard Tatschl https://orcid.org/0000-0001-5198-4933 (član povjerenstva)
• Granter: University of Zagreb; Faculty of Mechanical Engineering and Naval Architecture; Zagreb
• Defense date and country: 2014-11-27, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Mechanical Engineering; General Mechanical Engineering (Construction)
• Universal decimal classification (UDC): 621 - Mechanical engineering. Nuclear technology. Machinery

Abstract

The research and study presented in this thesis represent the development and validation of new turbulence, ignition and combustion sub-model that are integrated into the cycle-simulation of SI (spark-ignition) engines. The turbulence modeling was performed by the application of new k-ε sub-model while the new quasi-dimensional sub-models were developed to describe the ignition and combustion phenomena. The cycle-simulation results obtained with the application of developed sub-models were compared with the available 3-D CFD results over different operating conditions of several SI engines and with the experimental data of single cylinder SI engine. For each engine the single set of constants was applied and the cycle-simulation results showed a very good agreement with the 3-D CFD and experimental data.The research presented in this thesis resulted in the following scientific contributions:The development of new turbulence sub-model that is able to predict the progress of in-cylinder turbulence close to the 3-D CFD results.The development of new quasi-dimensional ignition model (QDIM) that is able to capture the effects of different in-cylinder conditions and spark plug designs on the early flame kernel growth as well as the multiple breakdowns and misfire conditions.Possibility to analyze the effects of different engine geometries and parameters on output performances with the presence of CCV (cycle-to-cycle variations) and within the reasonable computational time.

Abstract (croatian)

Istraživanje opisano u doktorskom radu predstavlja razvoj i validaciju novih podmodela za modeliranje turbulencije, stvaranja jezgre plamena i izgaranja koji su ugrađeni u simulacijski model radnoga ciklusa Ottova motora. Modeliranje turbulencije provedeno je primjenom novoga k-ε podmodela, a novi kvazidimenzijski podmodeli razvijeni su za proračun stvaranja jezgre plamena i izgaranja. Rezultati simulacija radnoga ciklusa Ottova motora uspoređeni su s dostupnim rezultatima 3-D CFD proračuna za različite radne uvjete nekoliko Ottovih motora, kao i s eksperimentalnim podatcima jednocilindarskoga motora. Jedinstveni skup konstanti primijenjen je za svaki motor te se simulacijski rezultati radnoga ciklusa Ottova motora vrlo dobro poklapaju s rezultatima 3-D CFD proračuna i eksperimentalnim podatcima. Istraživanje predstavljeno u ovom doktorskom radu rezultiralo je sljedećim znanstvenim doprinosima: 1) Razvoj novoga podmodela za proračun turbulencije u cilindru Ottova motora kojim se mogu postići rezultati bliski rezultatima 3-D CFD proračuna, 2) Razvoj novoga kvazidimenzijskoga podmodela za proračun stvaranja jezgre plamena kojim se mogu obuhvatiti utjecaji različitih uvjeta u cilindru motora i različite geometrije elektroda svjećice na rast jezgre plamena kao i efekti višestrukih proboja električne iskre i izostanka paljenja te 3) Mogućnost analize utjecaja različitih geometrija motora i njihovih radnih parametara na performanse Ottova motora uz prisutnost cikličkih varijacija i unutar prihvatljivoga proračunskoga vremena.

• Keywords: spark-ignition engine; combustion; cycle-simulation; turbulence; ignition; cycle-to-cycle variations
• Keywords (english): Ottov motor; izgaranje; simulacija radnog ciklusa; turbulencija; zapaljenje; cikličke varijacije
• Language: english
• URN:NBN: urn:nbn:hr:235:552575
• 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: 2020-04-27 21:31:45