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고온 예열 공기에 의한 난류 비예혼합 화염의 연소 특성
곽지현,전충환,장영준,Kwark, Ji-Hyun,Jeon, Chung-Hwan,Chang, Young-June 대한기계학회 2003 大韓機械學會論文集B Vol.27 No.5
An experiment using high preheated air in a turbulent non-premixed flame was performed to investigate the effects of high preheated air on the combustion characteristics. Combustion using high preheated and diluted air with flue gas is a new technology which enables NO emission to be reduced. In this study, Na was used as diluent and propane as fuel. Combustion characteristics, especially the distributions of the flame temperature, NO concentration and OH radical intensity were examined under the condition of 300 K, 600 K, 1000 K in terms of the combustion air temperature, and also under the condition of the dilution level from 21% to 13% in terms of oxygen concentration. As the preheated air temperature increased, it appeared that the flame length became shorter, maximum flame temperature increased, the reaction region moved to upstream, and NO concentration increased, but the flame temperature's fluctuation was reduced. In opposite, it was shown with decrement of oxygen concentration at the maximum temperature that both maximum value and the gradient of the flame temperature decreased, and NO emission also decreased considerably, but its fluctuation became larger, being inclined to be unstable.
산소부화공기가 동축 비예혼합 제트의 연소특성에 미치는 영향 (II) - 화염의 구조와 온도분포 -
곽지현,전충환,장영준,Kwark, Ji-Hyun,Jeon, Chung-Hwan,Jang, Young-June 대한기계학회 2004 大韓機械學會論文集B Vol.28 No.2
Combustion using oxygen enriched air is known as a technology which can increase thermal efficiency due to increase of the flame temperature. Flame shapes, schlieren photos, OH radical chemiluminescence and local flame temperature were examined as a function of OEC(Oxygen Enriched Concentration) in a coaxial non-premixed jet. With increase of OEC, flame length and width decreased, but its brightness increased significantly, and the size of vortices in the flame also increased. Especially, the reaction around the flame surface became active. The strong OH intensity appeared to be made and moved from middle stream to upper one with increase of OEC, which shows combustion reaction in the upper stream becomes more dominant In addition, the temperature distributions of the flames showed similar tendency with OH radical intensities. A flame with high temperature and strong stability was obtained with increasing OEC of the coflow.
곽지현,전충환,장영준,Kwark, Ji-Hyun,Jun, Chung-Hwan,Jang, Young-June 대한기계학회 2003 大韓機械學會論文集B Vol.27 No.8
An experiment was performed to investigate lift-off, blow-off and combustion characteristics of a lifted coaxial diffusion flame according to fuel jet and air velocity. A jet diffusion flame which is attached on the nozzle rim begins to be lifted with increase of air velocity, and finally becomes blow-off at higher air velocity. In experiment, blow-off limit increased with increase of fuel jet velocity, however lift-off occurred at lower air velocity. Flame structure and combustion characteristics were examined by schlieren photos, temperature distributions and emission concentration distributions. Flame temperature became higher at midstream and its RMS became larger at up and downstream with increase of air velocity. Local NO concentration decreased but $CO_2$concentration increased with increase of air velocity, which shows combustion reaction becomes close to be stoichiometric at higher air velocity in spite of lift-off.
곽지현,정용기,전충환,장영준,Kwark, Ji-Hyun,Jung, Yong-Ki,Jun, Chung-Hwan,Chang, Young-June 대한기계학회 2003 大韓機械學會論文集B Vol.27 No.4
An experiment in a turbulent non-premixed flat flame was carried out in order to investigate the effect of swirl number on the flow and combustion characteristics. First. stream lines and velocity distribution in the flow field were obtained using PIV method. In contrast with the axial flow without swirl, highly swirled air induced stream lines along the burner tile. and backward flow was caused by recirculation in the center zone of the flow field. In the combustion. the flame with swirled air also became flat and stable along the burner tile with increment of the swirl number. Flame structure by measuring OH and CH radicals intensity and by calculating Damkohler number(Da) and turbulence Reynolds number(Re$_{T}$) was examined. It appeared to be comprised in the wrinkled laminar-flame regime. Backward flow by recirculation of the burned gas decreased the flame temperature and emissions concentrations as NO and CO. Consequently, the stable flat flame with low NO concentration was achieved.d.
곽지현(Kwark, Ji-Hyun),김종권(Kim, Jong-Kwon) 한국화재소방학회 2008 한국화재소방학회 학술대회 논문집 Vol.2008 No.춘계
Fire-fighters are struggling against heat and dense smoke by fire when it occurs at the basement or the inner place of a building. An indoor fire-fighting robot with well heat-resistance, great searching cameras and good extinguishing ability has been developed. It never suffocate, coming into the fire district and extinguishes fire directly. In this study, several experiment was conducted to evaluate field working ability of the fire-fighting robot. As a result, a series of passing obstacles, finding fire place and fire suppression by the remote controlling with image information appeared satisfactory.
곽지현(Kwark, Ji-Hyun),최정민(Choi, Jung-Min),안병호(An, Byung-Ho),김범규(Kim, Bum-Kyue),박용환(Park, Yong-Hwan) 한국화재소방학회 2009 한국화재소방학회 학술대회 논문집 Vol.2009 No.춘계
화재발생시 가장 주요한 사망원인인 유독가스의 제어와, 소방관의 소화활동을 돕기 위한 제연설비는 각 구성품이 유기적으로 동작하는 시스템을 이루기 때문에 전체의 조화도 중요하지만, 기본적으로 각 설비요소가 제 기능을 발휘할 때 전체 시스템의 제연성능을 확보할 수 있게 된다. 그러나 현재 법으로 규정된 국내기준은 주요 구성품별 성능을 제대로 평가할 수 있는 방법 및 기준이 없어 본 연구를 통하여 배연창의 성능평가기술을 개발하고 항목별 성능시험을 실시하여 평가방법의 적합성을 검토하고 국가표준을 만들기 위한 기초 자료로 제공하고자 한다.