Seminar: An Ignition Regime Diagram and Its Implications for Prediction of Pre-ignition and Super-knock in IC Engines

Abstract

“Mild” and “strong” ignition phenomena have been experimentally observed in shock tubes and rapid compression machines in which the mixture condition is expected to be nearly homogeneous. The “mild” ignition behavior is attributed to early auto-ignition of hot spots leading to ignition front propagation, and is considered to be the main cause for the discrepancies in the prediction of the ignition delay times. The present study reports 1D and 2D parametric studies of computational simulations to represent the distinct ignition characteristics. Further scaling consideration leads to a diagram to map out parametric conditions in which different ignition regimes are identified. The study is extended to explaining some anomalies observed in shock-tube experiments. The implications in the context of pre-ignition and super-knock in modern internal combustion engines will also be discussed.

About the Speaker

Hong G. Im received his B.S. and M.S. in from Seoul National University, and Ph.D. from Princeton University.  After postdoctoral researcher appointments at the Center for Turbulence Research, Stanford University, and at the Combustion Research Facility, Sandia National Laboratories, he held assistant/associate/full professor positions at the University of Michigan. He joined KAUST in 2013 as a Professor of Mechanical Engineering. He is a recipient of the NSF CAREER Award and SAE Ralph R. Teetor Educational Award, and is an Associate Fellow of AIAA and a Fellow of ASME. He has also served as an Associate Editor for the Proceedings of the Combustion Institute, and is currently on the Editorial Board for Journal of Combustion. Professor Im’s research and teaching interests are primarily fundamental and practical aspects of combustion and power generation devices using high-fidelity computational modeling. Recent research topics include direct numerical simulation of turbulent combustion at extreme conditions, bluff-body flame stabilization mechanism, modeling of low grade and alternative fuels, spray and combustion modeling in advanced internal combustion engines, advanced models for turbulent sooting flames, electrical field effects on flames, and combustion characteristics of high hydrogen content fuels for advanced gas turbine applications.

Hosted by Professor Seung Hyun Kim