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Experimental Status on Monodisperse Drop Formation in Electrohydrodynamic Atomization
( Kian Sung ),( Chang Sik Lee ) 한국액체미립화학회 2005 한국액체미립화학회 학술강연회 논문집 Vol.2005 No.-
This paper was performed to explore the liquid breakup and atomization characteristics for the classification of drop formation mode and background of uniform droplets generation in electrohydrodynamic atomization according to the changing of experimental parameters such as nozzle material (stainless steel, teflon), fluid flow rate, applied electrical field and intensity, and frequency. In results, from the classification map of drop formation modes according to the variation of applied AC voltage and frequency at a stainless nozzle, the droplets size was smaller than the outer diameter of the nozzle tip relatively in the spindle mode. The transition points became clearly to be moved toward the high applied voltage by rising the applied AC frequency beyond 450 ㎐. Also, the droplet radius can be observed quite small in the frequency bandwidth of 350 450 ∼ ㎐. The droplet radiuses decrease as the applied voltage increase for a fixed applied AC frequency within the range from 50 ㎐to 400 ㎐. Over 400 ㎐, the relation between the power intensity and the droplet size was not consistent with a continuous mechanism of liquid breakup. Thus, it is showed that the droplet size distribution using the teflon nozzle was analogous to the results of stainless steel, but the droplet size was bigger than the one of stainless steel relatively in case of a teflon nozzle.
분산제어(DSI)기법을 적용한 에어백 제어기의 설계 및 운영체제 개발
성기안(kian Sung),김익환(Ik Hwan Kim),이창식(Chang Sik Lee) 한국자동차공학회 2003 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
The DSI technology in the side satellite sensors of an airbag ECU which are applied to decide side collisions effectively has been studied recently for common and multiple uses. The side satellite sensor with DSI technology can interface to the two-wire DSI bus using a combination of pulse length encoded voltage levels for transmission of data to remote peripheral units, and can apply to the different vehicles with no software calibration. The DSI is intended as a robust serial interface system suitable for automotive body applications including airbag safety system. <br/> The new airbag ECU was set up with the airbag firing loop ICs with 6 channels (4 frontal channels and 2 side channels) for DC firing and firing loop monitoring, a micromachined capacitive accelerometer with a 2-pole Bessel 400㎐ S/C filter, a multifunctional power supply IC, and the DSI digital and physical ICs. The applied MC9S12DJ256 microcontroller is the next generation of the higher performance and equip with a real time OS and a new crash recognition algorithm. The real time OS is observed the several functions as the internal and external fault diagnostic function, a communication function, and a crash history recording function.<br/> The time-to-fire of the airbag ECU is in qualitative agreement with the requirement time-to-fire of OEM vehicle maker. We have obtained the satisfactory results and wish to future study about an advanced airbag ECU using this technology.
Effect of Mixing Ratio of Biodiesel on Breakup Characteristics of a Single Droplet
( Yop Kim Sa ),( Sung Wook Park ),( Kian Sung ),( Haeng Mook Cho ),( Chang Sik Lee ) 한국액체미립화학회 2005 한국액체미립화학회 학술강연회 논문집 Vol.2005 No.-
In this paper, the breakup characteristics of a single droplet were analyzed as a function of mixing ratio of bioidesel. In order to investigate the effects of high surface tension and viscosity of biodiesel on the breakup mechanism of single droplet, the experiments were performed at various mixing ratios of biodiesels. In addition, the physical properties such as density, kinematic viscosity and surface tension of the biodiesel blended fuels were measured to study the relations between the non-dimensional numbers such as Weber number and Reynolds number, and the breakup mechanism. The experimental apparatus consisted of a droplet generation system, an air flow nozzle, a light source, a long distance microscope and a CCD camera. In the first stage breakup region, the droplet deformation rate was measured in order to reveal out the effect of high surface tension and kinematic viscosity on the deformation of a single droplet. The results of this experiment showed that the higher surface tension and viscosity of biodiesel prevent the disintegration of liquid droplet. Also the breakup mechanism is transited at higher relative velocity as the mixing ratio is increased.
[가솔린엔진부문] 공기 보조 인젝션 시스템의 성능 개선에 관한 실험적 연구
최우석(Wooseok Choi),성기안(Kian Sung),이창식(Changsik Lee) 한국자동차공학회 2000 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
In order to improve the atomization performance of conventional fuel injector, air-shrouded injector has been developed Aim of this study is to maintain atomization performance of air-shrouded injection system by using external equipment at the region except idling. In this experimental study, the spray characteristics of air-shrouded injector were investigated according to shrouding air pressure by using phase Doppler particle analyzing system. The manifold pressure sensor and modified injector with air- shrouded system are inserted the intake manifold, and the control unit detects the signal of manifold pressure and the engine speeds. The effects of modified air-shrouded system such as fuel consumption and emission characteristics are compared the results of conventional air-shrouded injection system with the air-shrouded injector. Based on the experimental results, it is found that the air-shrouded injection system with modified injector by the air-assisted control device shows the improvement on the spray characteristics and atomization performance of liquid fuel
압축착화 엔진에서 디젤-가솔린 Dual Fuel이 연소 및 배기 특성에 미치는 영향
권석주(Seokjoo Kwon),차준표(Junepyo Cha),성기안(Kian Sung),박성욱(Sungwook Park) 한국연소학회 2011 한국연소학회지 Vol.16 No.1
The present study describes the characteristics of combustion and exhaust emissions in compression ignition engines using diesel-gasoline dual fuel. For investigating combustion characteristics, diesel fuel was injected directly in a single-cylinder compression ignition engine with a common-rail injection system and gasoline fuel was injected into a premixed chamber installed in an intake port. In order to investigate exhaust emission characteristics, exhaust gas was measured by emission analyzer and smoke meter. The experimental results showed that cases of diesel-gasoline dual fuel combustion exhibited extended ignition delay and reduced peak combustion pressure compared to those of directly injected diesel fuel cases. Furthermore, premixed gasoline-air mixture reduced NOx emissions due to low peak of rate of heat release (ROHR).
디젤-에탄올 혼합연료의 다단 분사가 디젤 엔진 성능 및 배기물 특성에 미치는 영향
노현구(Hyun Gu Roh),이두진(Doo Jin Lee),성기안(Kian Sung),이창식(Chang Sik Lee) 한국자동차공학회 2011 한국자동차공학회 부문종합 학술대회 Vol.2011 No.5
This study is to investigate the effect of the multiple injections on the emission characteristics and engine performance of ethanol blended diesel fuel in a 4 cylinder light-duty diesel engine. In order to perform the influence of multiple injections and diesel-ethanol blended fuel in a passenger diesel engine, the injection strategy was controlled with pilot injection, double pilot injections, and one main injection at various experimental conditions. The experimental apparatus is consisted of DI diesel engine, EC dynamometer, multi-stage injection control system, and exhaust emissions analyzer. The results showed that diesel-ethanol blended fuel had longer ignition delay than those of diesel fuel. Also the effects of diesel-ethanol blended fuel on the exhaust emissions such as NOX and soot emissions were discussed under the various test conditions.