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플레임트랩에 의한 메탄-공기 예혼합기의 연소특성에 관한 연구
김덕호(Deokho Kim),이재효(Jaihyo Lee),최수진(Sujin Choi),조규백(Gyuback Cho),정동수(Dongsoo Jeong) 한국자동차공학회 2005 한국 자동차공학회논문집 Vol.13 No.2
Exhaust gas emissions from internal combustion engines are one of the major sources of air pollution. And, it is extremely difficult to increase gasoline engine efficiency and to reduce NOx and PM (particulate matter) simultaneously in diesel combustion. This paper offers some basic concepts to overcome the above problems. To solve the problems. a recommended technique is CAI(controlled auto-ignition) combustion. In this paper, a !lame trap was used to simulate internal EGR(exhaust gas recirculation) effect.<br/> An experimental study was carried out to find combustion characteristics using homogeneous premixed gas mixture in the constant volume combustion chamber(CVCC). Flame propagation photos and pressure signals were acquired to verify the !lame trap effect. The flame trap creates high speed burned gas jet. It achieves higher flame propagation speed and more stable combustion due to the effect of geometry and burned gas jet.
박경준(KyungJun Park),이기준(KiJun Lee),Bettar El Hadi,이재효(Jaihyo Lee),신동일(Dongil Shin) 한국가스학회 2011 한국가스학회지 Vol.15 No.3
본 연구에서는 미국 NIST의 Fire Dynamics Simulator (FDS) ver. 5.4.8을 이용하여 지하철 터널 안의 지하철에서 화재가 발생한 경우에 터널에 설치된 환기팬의 제연효과를 검증하였다. 시뮬레이션을 위해 서울 지하철의 실측자료를 활용하여 지하터널과 지하철을 모델링 하였다. 이를 바탕으로 환기용량을 2.0~3.0 ㎧ 범위에서 변화시키면서 CO와 CO₂의 제거 효율을 예측한 결과, 0.5 ㎧의 용량 증가에 의해 평균 35 % 이상의 제거효과가 있음을 확인하였다. 또한 FDS의 결과값이 전체 그리드 개수와 크기에 영향을 받는 점을 고려하여 정확한 결과값을 얻기 위해 FDS의 그리드 민감성을 검토하였다. 그리고 그리드 크기를 변화시켜 CO와 CO₂ 농도 산출값과 계산에 걸리는 시간을 비교한 결과를 바탕으로 최적의 그리드를 선정하여 시뮬레이션에 적용하였다. In this study, we investigate simulation studies to confirm the removal of smoke through ventilation when the subway car is on fire and stopped in an underground subway tunnel, by using Fire Dynamics Simulator (FDS) which is being upgraded by NIST. The structure of subway tunnel and train for simulation modeling are based actual data from Seoul metropolitan subway. The main purpose of this study is to assure the removal efficiency of the ventilation when changing the ventilation capacity between 2.0 ㎧ and 3.0 ㎧. The results of the study shows that carbon monoxide (CO) and carbon dioxide (CO₂) are reduced by about 35% as the ventilation capacity is increased by 0.5 ㎧. This study also performs the grid sensitivity verification of FDS for improved accuracy of the results. To find the effective size of the grid, three cases are simulated and the results are compared.
배플의 종류에 따른 지하철 터널내 자연환기구에서의 풍량증가에 관한 실험적 연구
홍승찬(Seungchan Hong),김영모(Youngmo Kim),Zhou qike,이재효(Jaihyo Lee) 대한기계학회 2010 대한기계학회 춘추학술대회 Vol.2010 No.11
In this study, the model was based on the natural ventilating opening of Jegi-dong station whose ventilation system is using train wind. The rate of reduction of tunnel, ventilation opening, and train was 1/20 and the driving the train model designed for two-way moving was controlled by using DC servomotor and computer. Also, the velocity of the model was controlled by being based on the model scale. To understand and measure the ventilation characteristics occurring while the model is driving, anemometer and manometer were set in the ventilating opening. The experimental study for efficient increased air volume was conducted positioning the baffles of different sizes in the natural ventilating opening. The result of the change of airflow rate when the baffle was installed improved by up to about 40% in maximum.