Dr. Jungho Sohn学术报告会
发布时间:2025-07-31   阅读:307

题目:Influence of Boundary Layer Turbulence on the Dynamics of Lean Hydrogen Flames

时间:2025年7月31日 14:30-16:30

地点:williamhill威廉希尔官网 F301会议室

邀请人:李玉阳 教授(航空动力研究所)


Biography

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Jungho Sohn is currently pursuing his Ph.D. in the Department of Aerospace Engineering at the Korea Advanced Institute of Science and Technology (KAIST). His research focuses on hydrogen flame, flashback, direct numerical simulation, and combustion modeling. He earned his M.S. and B.S. in mechanical engineering from Yonsei University and had experience as a postgraduate researcher at the Korea Institute of Industrial Technology (KITech). In addition, he has served as a visiting researcher at the University of California, Berkeley.


Abstract

Direct numerical simulations of lean premixed V-shaped hydrogen flames in a turbulent channel flow were conducted to study the characteristics of flow velocity and flame speed of lean hydrogen flames. In addition, a robust method to extract the laminar flame speed and the flow velocity just upstream of the flame front, named the approaching flow velocity on a moving flame, was developed using the G-equation framework. The results show that the flame speed and the approaching flow velocity are considerably affected by the flame front topology. Furthermore, the difference between these two values was labeled as a flashback velocity to investigate the possibility and characteristics of boundary layer flashback occurrence. Investigating quantified probabilities shows that flashback velocity values are scattered and even become negative (local flashback), which occurs mainly in the flame cusp regions. However, the flame in the cusp regions cannot cause the global flame flashback, as the flame cusps are inherently located on the rear sides of the flame and are quickly destroyed by flame folding. Conversely, in the flashback velocity on flame bulge regions tends to be skewed negatively, implying potential propagation upstream compared to the average flame movement.