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김덕줄,최동석,황순철 釜山大學校生産技術硏究所 1999 生産技術硏究所論文集 Vol.56 No.-
가솔린 와류형 고압 인젝터로부터 분사된 연료의 증발 거동을 exciplex 형광법을 사용하여 조사하였다. exciplex 형광법을 적용하기 위해 용매로 헥산, 참가제로 플루오로벤젠과 DEMA를 체적비로 각각 89%, 2%, 9% 혼합하였다. 결과로서 증발조건과 비증발조건에서 액상과증기상의 신호를 확인하였고, 분사후 경과시간에 따라 각각의 상의 공간분포의 변화를 측정하였다. 분무의 축방향으로의 증발보다는 분무반경방향으로의 증발이 더 활발히 진행되었다. 또한 순수한 증기상만이 차지하는 면적은 분사기간의 1/3지점에서 액상의 면적과 같아졌으며 그 이후는 급격히 증가하였다. This work was performed to provide qualitative information on the vaporization of fuel using exciplex fluorescence method in a spray from high-pressure swirl injector. Dopants used were 2% fluorobenzene and 9% DEMA(diethyl-methyl-amine) in 89% solution of hexane by volume respectively. As a result, liquid and vapor phases were compared under both evaporating and non-evaporating conditions, and each phase was illustrated with time after injection. Vaporization along the radial direction had larger activity than along the axial direction. The area of only vapor phase was approximated to that of liquid phase at about 1/3 of injection duration time, and after that time, it was greatly incrased.
A New Flame-Stabilization Technology for Lean Mixtures
Kim, Duck-Jool,Choi, Gyung-Min The Korean Society of Mechanical Engineers 2000 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.14 No.4
The development of a low-pollution burner is important for saving energy and preserving the environment. A low-pollution burner can be produced by lean-mixture combustion and general combustion technology. The flammable limit of premixed flame is narrower than that of diffusion flame. Producing a lean mixture of fuel results in an effective combustion condition, which in turn produces high load and low pollution. In this study, it was found that the influx of $Q_2$ had an effect on extending the lean flammable limits and flame stabilization in a doubled jet burner. And the flame, consisting of small eddies, can be stabilized by the nozzle neck phenomena.
부분 예혼합 화염의 연소실 압력이 연료별(메탄, 에틸렌, 프로판) 연소특성과 국소 화염 반응에 미치는 영향
김종률(Jong-ryul Kim),손제하(Je-ha Son),노영구(Young-gu Noh),김윤동(Yun-dong Kim),최경민(Gyung-min Choi),김덕줄(Duck-jool Kim) 한국연소학회 2010 한국연소학회지 Vol.15 No.4
An experimental study was conducted for three different fuels(CH₄,C₂H₄ and C₃H?) to investigate the combustion characteristics and the local reaction intensity with combustor pressure(-30kpa~30kpa). Regardless of fuel composition, EINOx decreased with reducing pressure decreased. Structure and combustion characteristics were also largely affected by the combustor pressure. In addition, reaction intensity in terms of the changing combustor pressure and equivalence ratio was investigated. Combustion reaction in higher than atmospheric pressure was very active than the lower combustor pressure. When the combustor pressure is lower than the atmospheric pressure, the overall reactivity is noticeably enhanced due to the elevated diffusion process of unburned mixture. It was found that the combustion characteristics of the methane and propane flames are considerably influenced by the pressure while those of ethylene flame are less sensitive to the combustor pressure.
노영구(Young-Gu Noh),김종률(Jong-Ryul Kim),김태형(Tae-Hyung Kim),서상일(Sang-Il Seo),김성철(Sung-Chul Kim),나종문(Jong-Moon Na),최경민(Gyung-Min Choi),김덕줄(Duck-Jool Kim) 한국연소학회 2009 KOSCOSYMPOSIUM논문집 Vol.- No.39
An experimental study was performed to investigated the effect of the changing combustor pressure(-30㎪ ~ 30㎪), combustion characteristics were investigated by comparison between the local chemiluminescence intensity and the local temperature distribution of CH₄, C₂H₄ and C₃H?. The our previous experimental works, we can see the activity combustion for lower pressure than atmospheric condition about CH₄. In present study, the local mean temperature showed the uniform distributions for lower pressure index, Ф=1.2. C₂ <SUP>*</SUP>/CH<SUP>*</SUP> intensity ratio, also showed high level for one. EINOx decreased with decreasing pressure index for all fuels. However, C₂H₄ shows other characteristics by diffusion coefficient and burning velocity, which indicates higher effect of burning velocity than changing combustor pressure.
스월화염에서 연소실 압력 변동에 의한 국소 반응강도의 특성
노영구(Young-Gu Noh),김종률(Jong-Ryul Kim),김태형(Tae-Hyung Kim),서상일(Sang-Il Seo),김성철(Sung-Chul Kim),나종문(Jong-Moon Na),최경민(Gyung-Min Choi),김덕줄(Duck-Jool Kim) 한국연소학회 2009 한국연소학회지 Vol.14 No.4
An experimental study was performed to confirm the effect of the changing combustor pressure(-30~30 kpa), combustion characteristics were investigated by measuring the local chemiluminescence intensity, the local temperature distribution and emission. In order to investigate combustion ones, the combustor pressure index(P<SUP>*</SUP>) was controlled in the range of 0.7~1.3 for each equivalence ratio in the present combustion system, where P<SUP>*</SUP> is defined as the ratio of absolute pressure to atmospheric one. The local mean temperature showed the uniform distributions for lower pressure index, which increased with increasing equivalence ratio. The mean OH* chemiluminescence intensity, showed high level for lower pressure index for Φ≥1.0 conditions. EINOx decreased with decreasing pressure index for overall equivalence ratio conditions.
석탄 산처리에 따른 연료의 표면 물성 변화와 직접탄소 이용 연료전지 성능 간의 상관관계 분석
김동헌(Dong Heon Kim),엄성용(Seong Yong Eom),최경민(Gyung Min Choi),김덕줄(Duck Jool Kim) 대한기계학회 2016 大韓機械學會論文集B Vol.40 No.11
본 논문에서는 역청탄인 Glencore 탄을 염산과 질산수용액을 이용하여 산 처리하고 원탄과 산 처리 된 석탄의 물리, 화학적 비교분석과 직접탄소 이용 연료전지(Direct Carbon Fuel Cell, DCFC)의 성능비교 분석을 수행하였다. 석탄의 물성들을 분석하기 위해 열중량 분석과 가스 흡착법, X선 광전자 분광법을 수행하였다. 열중량 분석을 통해 연료의 열적 반응성이 증가하였음을 알 수 있었고, 가스 흡착법 결과로 기공의 평균지름은 변화가 없었지만 표면적은 감소함을 알 수 있었다. X선 광전자 분광법에서는 HNO₃ 처리의 경우 가장 높은 산소/탄소 비율을 보였고, 이를 통해 다양한 표면 산소작용기가 증가한 것을 확인하였다. 연료의 표면 물성과 전기화학 성능을 비교한 결과, 표면의 산소 성분의 변화가 DCFC의 성능 향상에 가장 큰 영향을 미침을 알 수 있었다. Coal modified by acid treatment was investigated to analyze the correlation between the cell performance and electrochemical parameters in a direct carbon fuel cell (DCFC). The fuels were subjected to thermogravimetry analysis, gas adsorption test, and X-ray photoelectron spectroscopy to investigate the fuel properties and surface characteristics. After the treatment of raw coal, the thermal reactivity of the treated fuels increased, and the specific surface area decreased, though the mean pore diameters of three fuels were similar. The coal treated by HNO₃ showed the highest ratio of oxygen to carbon, and also an increase in the surface oxygen groups on the fuel surface. Through comparison between the fuel surface properties and electrochemical performance, it was confirmed that the surface oxygen groups have an influence on the improvement in the DCFC performance.
롤링 피스톤형 로타리 압축기에서의 롤러와 실린더 간극 간 누설 유량 예측
김건우(Geon-woo Kim),노기율(Ki-youl Noh),민병채(Byung-chae Min),송상진(Sang-jin Song),나상경(Sang-kyung Na),윤태승(Tae-seung Yoon),양장식(Jang-sik Yang),최경민(Gyung-min Choi),김덕줄(Duck-jool Kim) 대한설비공학회 2016 대한설비공학회 학술발표대회논문집 Vol.2016 No.6
Functional formula of the flow coefficients for the radial clearance in a rolling piston rotary compressor was developed by the experiments and CFD (Computational Fluid Dynamics) to improve the accuracy of a compressor performance simulation. The experiments and CFD simulation were conducted to obtain the flow coefficients at the radial clearance with the assumptions of incompressible flow and steady state. The experiments were carried out with the variation of pressure ratio and low upstream pressure using the nitrogen as a working fluid. The validated CFD model was adopted to calculate the flow coefficients with change area of the radial clearance and high upstream pressure. The functional formula obtained from the results of the CFD calculation was applied to compressor performance simulation for calculating the leakage through the radial clearance. The results of compressor simulation with the functional formula showed tolerable errors with the experimental data of the compressor calorimeter in terms of EER (Energy Efficiency Ratio). Thus, the function of the flow coefficients may be acceptable for prediction of leakage through the radial clearance under the various conditions.
직분식 가솔린 엔진에서 피스톤 캐비티 반경에 따른 연료 거동 분석
김태안(Tae-An Kim),강정중(Jeong-Jung Kang),김덕줄(Duck-Jool Kim) 대한기계학회 2003 대한기계학회 춘추학술대회 Vol.2003 No.11
This study was performed to investigate the behavior of vapor phase of fuel mixtures with different piston<br/> cavity diameters in a optically accessible engine. The images of vapor phases were measured in the motoring<br/> engine using exciplex fluorescence method. The conventional engine was modified as GDI engine with swirl<br/> flow. Fuel was injected into atmospheric nitrogen to prevent quenching phenomenon by oxygen. Injection<br/> pressure is 5.1MPa. Two dimensional spray fluorescence image of vapor phases was acquired to analyze spray<br/> behavior and fuel distribution inside of cylinder. Three injection timings were set at BTDC 180°, 90°and<br/> 60°. With a fuel injection timing of BTDC 60°, fuel-rich mixture was concentrated in near the cavity<br/> center. With a fuel injection timing of BTDC 90°, fuel-rich mixture level in the center region was highest in<br/> the S-type during the late compression stroke. With a fuel injection timing of BTDC 180°, fuel was not<br/> affected in a piston cavity and generally distributed as homogeneous mixture.