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Ph.D. Thesis Proposal by
Sayop Kim
(Advisor: Professor Caroline L. Genzale)
ON THE USE OF ADVANCED TURBULENT SPRAY AND COMBUSTION MODELINGS AT OMPRESSION IGNITION ENGINE RELEVANT CONDITIONS
3:30 PM, Thursday, February 15, 2018
Montgomery Knight Building Room 317
ABSTRACT:
This thesis seeks to investigate the turbulent mixing influence on spray atomization and combustion processes encountered in compression ignition diesel engines. Despite greater thermal efficiency of diesel engine, the nature of stratified air-fuel mixture and non-premixed flame gives rise to unacceptable levels of nitrogen oxides (NOx) and particulate matter (PM). However, recent advancement in diesel engine combustion strategies, e.g. low temperature combustion (LTC), has demonstrated promising pathways towards improvement in the engine-out pollutants. Therefore, such a new engine design concept requires more accurate modeling techniques applicable over a broader range of engine operating conditions than those of conventional engine strategies. In the notion of such challenges, this thesis aims to present successful implementation of advanced numerical modeling techniques in high-pressure spray atomization and resulting turbulent spray flame of interest.
In spite of successful use of existing spray atomization modeling, prior researchers have pointed out some degree of failure in LTC targeted injection strategies. Furthermore, finite rate and strong nonlinearity of chemistry influenced by local turbulent mixing still remain in challenges to account for in cost-efficient CFD analysis. In this context, a new attempt of hybrid spray primary breakup modeling is presented and demonstrated in successful application aimed at LTC technique. In addition, the Representative Interactive Flamelets (RIF) model and Tabulated Flamelet Model (TFM) approaches are also successfully implemented in open-source CFD framework, OpenFOAM and verified against the commercially available CFD software, CONVERGE. Ultimately this study demonstrates the implemented models’ viability for better capturing end-of-injection (EOI) induced transient spray combustion, often referred to as “combustion recession”, which plays a critical role in reduction of unburned hydrocarbon (UHC) and carbon oxides (CO) emissions in LTC engine strategies.
COMMITTEE MEMBERS:
Professor Caroline L. Genzale, School of Mechanical Engineering (Advisor)
Professor Jechiel Jagoda, School of Aerospace Engineering (Co-advisor)
Professor Joseph Oefelein, School of Aerospace Engineering
