Topic: Flame development and soot particles inside the cylinder of automotive-size diesel engines

Speaker: Dr.Sanghoon Kook，School of Mechanical Engineering，The University of New South Wales, Sydney, Australia.

Time: Oct. 28, 10：00 am—12:00 am

Venue: F307

Inviter: Prof. Li Tie

Abstract:
This talk introduces recent findings in four main areas of the UNSW’s Engine Research Group including (1) ethanol sprays and flame propagation in an optical petrol engine, (2) ethanol-diesel dual fuelling in a diesel engine, (3) diesel spray and flame development in an optical diesel engine, and (4) in-flame diesel soot particles, with particular emphasis on diesel flame and soot particles. One of the primary research goals of the group is to extend the knowledge developed on a free, quasi-steady diesel jet to a more practical wall-interacting jet in a running engine. In an automotive-size engine, the diesel flame experiences significant interactions with the surrounding piston wall quickly after the fuel injection resulting in complex and transient flame development. To clarify the transient behaviour of the wall-affected diesel flame, we performed high-speed imaging of hot soot luminosity, intensified imaging of OH* chemiluminescence, and laser-induced fluorescence imaging of fuel and OH. Results show interesting behaviour indicating preference for the wall-affected jet to have shorter flame lift-off length than that of the free jet. Possible mechanism for the observed behaviour is discussed in details including the re-entrainment of hot combustion products whereby the wall-affected jet causes hotter ambient gas incorporation into the incoming jet. For the same conditions, soot particles were extracted directly from the reacting jet by means of a thermophoretic probe, and analyzed using transmission electron microscopy (TEM) to clarify the soot structure. This is opposed to exhaust sampling and useful to gain fundamental insight about the structure of in-flame soot during key formation and oxidation stages.

Introduction of speaker 
Dr. Sanghoon Kook is a Senior Lecturer of the School of Mechanical Engineering and directs the UNSW Engine Research Laboratory. He also serves as Director of Research for the school. His expertise lies in optical/laser-based imaging diagnostics in an engine, advanced engine combustion, pollutants formation and alternative fuels. Before UNSW, Dr Kook was a post-doctoral researcher at U.S. Department of Energy's Sandia National Laboratories. Dr Kook earned his B.S. degree in Mechanical Engineering (2000), M.S. degree in Nuclear and Quantum Engineering (2002), and Ph.D. degree in Mechanical Engineering (2006) from KAIST. Dr Kook has authored more than 60 papers including a journal article received Horning Memorial "Best Paper" Award from Society of Automotive Engineers (2005). Also, he was named a winner of JSPS Invitational Fellowship administered by Australian Academy of Science (2011), a finalist of R&D category of Australian Engineering Excellence Award - Sydney Division (2012), and a recipient of SAE Teetor Educational Award (2013).