1. 제  목 : Advanced laser-based diagnostics: A versatile approach to combustion research

2. 연  사 : Dr. Jihyung Yoo (Oak Ridge National Laboratory)

3. 일  시 : 2013년 2월 28일 (목) 오후 4:30~5:30

4. 장  소 : 301동 1512-2호

5. 내용 : Combustion research is of paramount importance in developing cleaner and more efficient means of energy conversion as the demand for limited resources increase. Application of new and existing diagnostics can provide insights into complex chemical and physical processes during combustion phenomena. Laser-based diagnostics, in particular, offer unique capabilities of performing fast, non‐intrusive, and species‐specific measurements. This in turn can enhance predictive models, system designs, and control strategies required to improve performance and sustainability of combustion-based  energy systems.
  Two techniques are presented to demonstrate the utility and versatility of laser diagnostics in combustion research. The first technique, planar laser-induced fluorescence (PLIF), is used to develop diagnostic strategies for nitric oxide (NO) and carbon dioxide (CO2) in high-pressure premixed flames. The push towards higher pressure combustion necessitates laser diagnostics at these conditions which can obfuscate strategies optimized for near-atmospheric conditions. The proposed strategy successfully resolved ppm-levels of NO and measured fluorescence quantum yield of CO2 in flames up to 60bar. The second technique, tunable diode laser absorption spectroscopy (TDLAS), is used to develop exhaust gas recirculation (EGR) sensors in internal combustion (IC) engines. EGR is an effective method of reducing NOx emission, although excessive use can lead to unsteady engine behaviors. The sensor provided crank-angle resolved EGR fraction at various locations in the intake manifold and identified component designs that maximized engine stability and performance.

6. 연사약력
  Dr. Yoo received his B.S. and Ph.D. in mechanical engineering at Hanyang University and Stanford University, respectively. His research at Stanford focused on developing novel diagnostics for various high-temperature gas dynamics research such as imaging high-pressure premixed flames up to 60bar and shockwave bifurcation in near-wall flow fields as well as modeling fundamental spectroscopic parameters of important combustion-related
species such as nitric oxide, carbon dioxide, and  toluene.
  His current research at Fuels, Engines, and Emissions Research Center in Oak Ridge National Laboratory (ORNL) is primarily aimed at developing laser-based sensors for advanced IC engine applications in close collaboration with industry partners. He performed several field measurement campaigns at industry partners’ experiment facilities evaluating components and control strategies using sensors designed and built at ORNL. The sensor, patent pending, can provide much more detailed information on spatiotemporal engine flow dynamics than conventional gas analyzers thereby quickly identifying potential design and control
improvements and promoting faster technology development.

7. 문  의 : 기계항공공학부 송한호 교수 (☏ 880-1651)