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Sayop Kim
(Advisor: Prof. Caroline L. Genzale]
Will defend a doctoral thesis entitled,
Advancing Turbulent Spray and Combustion Models
for Compression Ignition Engine Simulations
On
Time: Jan 15th, 10:30am – 12:30pm
Location: MK325
Abstract
Three-dimensional Computational Fluid Dynamics (CFD) in in-cylinder turbulent combustion is considered an integral part of engine design progress, but rather a cost-prohibitive to apply over a broad range of engine relevant conditions. In spite of successful use of existing spray atomization modeling, prior researchers have pointed out some degree of failure in low-temperature combustion (LTC) targeted injection strategies. Furthermore, finite rate and strong nonlinearity of chemistry influenced by local turbulent mixing still remain in challenges. 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 is extensively assessed in terms of predictive capability against classical combustion model. The combustion model employed in this study are fully examined in the general diesel combustion metric, e.g., ignition delay and flame lift-off length as well as newly suggested test metric, combustion recession. The combustion recession has been recently identified, but still remain largely unknown. Since the governing physics of this phenomenon is characterized by turbulent mixing coupled with finite rate chemistry, this can be considered as a relevant test metric for turbulent combustion models. In addition, recent experimental studies have introduced a new non-sooting diesel combustion technique by manipulating direct injection method. The ducted fuel injection (DFI) has thus been demonstrated with its potential of low soot emissions. Knowing that the duct equipped ahead of injector nozzle was identified to enhance turbulent mixing, investigations of DFI combustion may prove the effectiveness of turbulence-chemistry interaction modeling. This thesis presents comprehensive understandings of aforementioned diesel combustion techniques in terms of several important physics keywords, e.g., turbulent mixing and detailed chemistry.
Committee
