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최성우(Sung Woo Choi),정성식(Sung Sik Chung),하종률(Jong Yul Ha),河島陽介(Yousuke Kawasima) 대한기계학회 2004 대한기계학회 춘추학술대회 Vol.2004 No.4
This study represented experimental research on the flat plate solar collector. For the flat plate Solar system, it is sensitive of the Global radiation. In Actually, it suppose to be dependent on the direct radiation. Also, the existing method's factors are depend upon Global radiation in the flat plate collector system. therefore it needs which is depend upon direct radiation. In this experiment, the flat plate collector is used for obtaining the method's factors of the direct radiation. As a result, the correct (τα)<SUB>e</SUB> is found out for practical value.
최하성(Ha-sung Choi),박종상(Jong-sang Park),하종률(Jong-yul Ha),정성식(Sung-sik Chung) 한국자동차공학회 2002 한국자동차공학회 지부 학술대회 논문집 Vol.2002 No.10
An experimental study was carried out to obtain fundamental data about effect of radical induced injection on the combustion of pre-mixture in a constant volume chamber with a tiny sub-chamber. Volume of the sub-chamber was set up to occupy less than 1.5% of whole combustion chamber volume, some narrow passage holes were arranged to induce simultaneous multi-point ignition in the main chamber by flame jets including radicals from the sub-chamber, and the equivalence ratios of pre-mixture in the main-chamber and sub-chamber were the same. And also, visualization for combustion process was performed in the main chamber.<br/> In the case of radical ignition(RI) method, the overall burning time including the ignition delay was very short to that of the spark ignition(SI) method. As diameter of the passage holes and the volume of sub-chamber increase, the combustion characteristic of the RI method was similar to that of the SI method.
최하성(Ha-sung Choi),박종상(Jong-sang Park),하종률(Jong-yul Ha),정성식(Sung-sik Chung) 한국자동차공학회 2002 한국자동차공학회 지부 학술대회 논문집 Vol.2002 No.3
An experimental study was carried out to obtain a series of fundamental data about radical controlled and induced injection effect on the combustion of pre-mixture in the main-chamber. The volume of the sub-chamber is set up to occupy less than 1.5% of whole combustion chamber, the equivalence ratio of pre-mixture in the main chamber and sub-chamber is uniform, and numerous narrow passage holes are arranged to induce simultaneous multi-point ignition in the main chamber by flame jets including radicals from the sub-chamber.<br/> In the case of radical ignition method(RI), the overall burning time including the ignition<br/> delay time became very short compared with that of the spark ignition method(SI).<br/> With the increase of the diameter of passage holes and the volume of the sub-chamber, the<br/> combustion characteristics of the Rl becomes similar to that of the Sl.<br/> By the result of the visualization of combustion in the main chamber, while the Sl shows<br/> the traditional flame propagation, the RI shows the phenomena as bulk combustion.<br/>
염정국,박종상,정성식,하종률,김시범,Yeom, Jeong-Kuk,Park, Jong-Sang,Chung, Sung-Sik,Ha, Jong-Yul,Kim, Si-Pom 한국자동차공학회 2007 한국 자동차공학회논문집 Vol.15 No.3
In this study, the effects of change in ambient gas viscosity on spray structure have been investigated in the high temperature and pressure field. To analyze the structure of evaporative diesel spray is important in speculation of mixture formation process. Emissions of diesel engines can be reduced by the control of the mixture formation process. Therefore, this study examines the evaporating spray structure in the constant volume chamber. The viscosity of ambient gas was selected as the experimental parameter, is changed from 21.7 mPa s to 32.1 mPa s by changing in ambient gas temperature. In order to obtain images of the liquid and vapor-phase of injected spray, exciplex fluorescence method was used in this study. The liquid and vapor-phase images were taken with 35mm still camera and CCD camera, respectively. Consequentially, it could be confirmed that the distribution of vapor concentration is more uniform in the case of the ambient gas with high viscosity than in that of the ambient gas with low viscosity.
저압 분사조건에 따른 직접분사 LPG의 분무 및 연소특성 연구
황성일(Seong-Ill Hwang),정성식(Sung-Sik Chung),염정국(Jeong-Kuk Yeom),이진현(Jin-Hyun Lee) 한국가스학회 2016 한국가스학회지 Vol.20 No.1
액화석유가스는 환경 친화적이며 에너지 효율성과 출력성능이 뛰어나 실용성이 높고, 경쟁연료에 비해 가격경쟁력이 우수하기 때문에 촉망받는 대체연료 중 하나로 간주된다. 스파크점화 엔진에서 직분식 기술은 엔진 체적효율을 눈에 띄게 증가시키며, 상대적으로 더 높은 연소효율이 가능한 성층급기를 이용해 엔진을 작동시킨다. 본 연구에서는 가솔린직접분사 엔진의 원리를 적용하여 가시화 시스템을 장착한 연소실을 설계하였다. 이를 통해 스파크점화직분식 LPG의 점화성과 화염전파 과정을 디지털 방식으로 기록하고 분석하였다. 이러한 연구의 결과는 스파크점화직분식 LPG 엔진의 설계 및 최적화를 위한 광범위한 기초 자료로서 기여하고자 한다. Liquefied petroleum gas is regarded as a promising alternative fuel as it is eco-friendly, has good energy efficiency and output performance, practically and has high cost competitiveness over competing fuels. In spark-ignition engine, direct injection technology improves engine volumetric efficiency apparently and operates engine using the stratified charge that has relatively higher combustion efficiency. This study designed a combustion chamber equipped with visualization system by applying gasoline direct injection engine principle. In doing so, the study recorded and analyzed ignition probability and flame propagation process of spark-ignited direct injection LPG in a digital way. The result can contribute as a basic resource widespread for spark-ignited direct injection LPG engine design and optimization extensively.
박종상,이태원,하종률,정성식,Park, Chong-Sang,Lee, Tae-Won,HA, Jong-Yul,Chung, Sung-Sik 대한기계학회 2000 大韓機械學會論文集B Vol.24 No.3
As the combustion process of CWM consists of the water evaporation, the release and combustion of volatile matter, and the combustion of char for every particle, it is more complex than that of existent liquid fuel. Though the many studies on CWM combustion have been carried out by the single droplet using hanging methods or the multiple droplet using atomization methods, any report don't presents definite solution about the effects by the initial water evaporation and combustion of volatile. When CWM is suddenly exposed in the high temperature surroundings, the internal water evaporates and then each droplet builds up pores. Besides, porosity rate changes along the temperature of surroundings, the composition ratio of CWM, and the initial diameter of droplet. In result, because it affects the whole combustion rate, the combustion of CWM has complex mechanism as compared with the combustion of liquid or gas fuel. Therefore, concentrating on porous structure of CWM, this study has proceeded to acquire the basic data on the CWM injection combustion and closely examines the effects of the first stage combustion on the whole combustion by measuring the diameter variations, pore rate, mass fraction burned, and the internal temperature changes of CWM droplet. The results demonstrate that $60{\sim}70%$ of initial mass is reduced during water evaporation and volatile combustion period, and swelling rate, mass faction burned, and density variation are greatly concerned with atomization of CWM etc.