와류형 고압인젝터의 초기분무의 분열 과도현상

최동석,김덕줄,고장권,Choi, Dong-Seok,Kim, Duck-Jool,Ko, Chang-Kwon 대한기계학회 1998 大韓機械學會論文集B Vol.22 No.8

The disintegration process of initial spray from high-pressure swirl injector was investigated at different injection pressures. The transient breakup phenomena that were difficult to observe at high injection pressure were easily observed at the low injection pressure of 0.4MPa. The effect of fuel remained inside a nozzle hole volume on the penetration of initial spray was also investigated. The disintegration process of initial spray could be classified four regions: the formation of mushroom shape, the first collision, the second collision, and the development of spray, The liquid film of cup shape was particularly found in the second collision region, and the growth ratio of its length and width at low and high injection pressures were compared.

UV광 측정용 아조벤젠 코팅된 FBG의 열적 효과 제거 및 파장 의존성에 대한 연구

최동석,김현경,안태정,Choi, Dong-Seok,Kim, Hyun-Kyoung,Ahn, Tae-Jung 한국광학회 2011 한국광학회지 Vol.22 No.2

본 논문에서는 ultraviolet (UV) 광의 세기를 원격으로 측정하기 위한 아조벤젠 (azobenzene) 코팅된 fiber Bragg grating (FBG)를 구현하였다. 아조벤젠 폴리머는 UV 광에 의해서 탄성이 변화하여 FBG의 코어 격자의 주기 변화를 유도하여 중심파장을 이동시킨다. 중심파장의 이동은 UV 광과 UV 이외의 파장대역의 빛에 의해서 복합적으로 발생하는데 중심파장의 이동량은 약 0.18 nm 이다. 측정의 정확성을 향상시키기 위해서 광원의 복사열에 의한 중심파장의 이동을 열차단 필터(thermal filter)를 사용하여 제거한 결과 중심파장의 이동량은 약 0.06 nm로 다소 감소하였지만 분석 결과 열에 의한 이동량이 충분히 제거된 것을 확인하였다. 또한 서로 다른 방법인 열경화법과 UV 경화법으로 각각 제작된 아조벤젠 폴리머를 이용하여 아조벤젠 코팅 FBG를 제작하였고, 각 제조법에 따른 UV센서로서의 적합성을 확인하였다. 몇 개의 밴드패스 필터(band pass filter)를 사용하여 파장에 대한 민감도를 측정한 결과, 단위 UV 세기당 중심파장의 이동량은 370nm 파장 밴드에서 가장 큰 값인 0.029로, 단파장 영역에서 반응성이 우수하다는 사실을 확인 하였다. 아조벤젠 폴리머의 흡수 스펙트럼과 아조벤젠 코팅 FBG의 파장 의존도가 서로 잘 일치하는 것을 확인하였다. In the paper, we have demonstrated an azobenzene-coated fiber Bragg grating (FBG) for monitoring ultraviolet light (UV) intensity in remote measurement. The elasticity of the coated azobenzene polymer is changed by the UV light, which induces a center wavelength change corresponding to the change of the FBG's grating period. The wavelength shift resulting from both UV light and other light with the wavelength out of the UV range was about 0.18 nm. In order to improve the accuracy of the measurement, the center wavelength shift caused by radiant heat of the light source was sufficiently removed by using a thermal filter. The amount of the center wavelength shift was consequently reduced to 0.06 nm, compared to the result without the thermal filter. Also, the FBGs coated by using azobenzene polymer were produced by two different methods; thermal casting and UV curing. Considering temperature dependence, UV curing is more suitable than thermal casting in UV sensor application of the azobenzene-coated FBG. In addition, we have confirmed the wavelength dependence of the optical sensor by means of four different band pass filters. Thus, we found out that the center wavelength shift per unit intensity is 0.029 [arb. unit] as a maximum value at 370 nm wavelength region and that the absorption spectrum of the azobenzene polymer was very consistent with the wavelength dependence of the azobenzene-coated FBG.

와류형 고압 분무의 속도 및 입경분포에 관한 연구

최동석,류경훈,차건종,김덕줄,Choi, Dong-Seok,Ryu, Kyung-Hoon,Cha, Keun-Jong,Kim, Duck-Jool 대한기계학회 1999 大韓機械學會論文集B Vol.23 No.10

High-pressure swirl injectors have usually been employed in Gasoline direct injection engines due to their spray characteristics and the feasibility of their control. Thus the microscopic characteristics of high-pressure swirl spray were investigated by PDA. The correlation between axial and radial velocities and the correlation between droplet size and axial velocity were examined with different axial and radial positions. Two dimensional droplet velocity and its number distribution with size-classified droplets were illustrated. The mean droplet velocity and its SMD were also analyzed at the center of spray, the position having maximum mean axial velocity, and the spray periphery using time dividing method. Finally, the structure of high-pressure swirl spray was presented with the size distribution and velocity profile of droplets.

블로바이가스 환기시스템과 엔진오일의 열화

최동석(Dongseok Choi),엄성복(Sungbok Eom),박용성(Yongseong Park),이종현(Jonghyun Lee),용기중(Geejoong Yong) 한국자동차공학회 2004 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-

The effect of blow-by gas ventilation system on the degradation of engine oil was investigated through the analysis of engine oil. Two different blow-by gas ventilation systems, which are an orifice type and a valve type, were tested on the urban road. The blow-by gas flow rate was characterized in the engine bench test. The degradation of the oil sample was analyzed in terms of viscosity, total acid number (T AN) and trace metal. It was found that the orifice type had a more significant effect on the degradation of the oil than the valve type. As test length of the vehicles increased, the effect of temperature on viscosity was bigger for the orifice type. The orifice type had higher TAN value and more trace metal. This degradation of the oil could form sludge within a cylinder head and a crankcase. Oil drain period suggested by the used oil analysis was within the drive distance of 6000km in the urban driving condition.

직분식 가솔린 가시화 엔진에서 분사시기에 따른 연소특성

최동석(Dong-Seok Choi),이용석(Yongseok Lee),최재준(Jaejoon Choi),배충식(Choongsik Bae) 한국자동차공학회 2002 한국자동차공학회 춘 추계 학술대회 논문집 Vol.2002 No.5_1

The mixture distribution and combustion characteristics in a DISI optical engine with a single cylinder were investigated under homogeneous and stratified charge modes. The process of mixture formation was observed using tracer Laser Induced Fluorescence (LIF) technique. 3-pentanone as tracer was employed. The 266nm harmonic beam of the Nd:YAG laser was used to excite the tracer in the motored engine. A part of piston cavity was made of quartz to visualize the processes of mixture formation. Two different injection timings, which are 270°BTDC and l15°BTDC, were set to simulate both charge modes. The effect of injection timings on the stratified mixture distribution and combustion was investigated Fuel distnbution surrounding the spark plug was particularly observed from LIF images. From these experimental information under non-combustion and combustion atmosphere, it will be predicted the region where pollutant emissions could be formed.

장자의 생명사상 연구

최동석(Dong-Seok CHOI) 대구가톨릭대학교 가톨릭사상연구소 2019 가톨릭사상 Vol.- No.58

본 논문은 “인간 생명”이라는 문제를 주제로 삼아 장자 ｢내편｣을 연구하였다. 장자는 어찌할 수 없는 세상의 조건 속에서 위협받지 않는 생명에 대해 고민하였고 그 답을 발견하였다. 이에 이 논문은 장자가 직접 지었다는 ｢내편｣을 새롭게 재조명하기 위해, ｢인간세(人間世)｣, ｢양생주(養生主)｣, ｢덕충부(德充符)｣, 그리고 ｢소요유(逍遙遊)｣ 편을 중심으로 살펴보았다. ｢인간세｣ 편에서는 인간이 처한 상황 즉 “어찌 할 수 없음”이라는 운명을 받아들여야 하는 측면과 이것과는 또 다른 인간의 “마음”이라는 측면을 살펴본다. 그리고 이어지는 ｢양생주｣ 편에서는 포정이 소를 해체해나가는 기술을 설명하면서 양생이 완성되는 모습을 보여준다. ｢덕충부｣ 편에서는 육체적 불구자들이 등장하는데, 이들이 곧 덕의 내적 충실을 표현하는 이들임을 확인할 수 있게 된다. 끝으로 ｢소요유｣ 편은 장자가 생각하는 인간이 도달할 수 있는 궁극적 경지 즉, 마음의 대자유를 표현하고 있다. 이 여정에서 참으로 사람을 사람답게 하는 마음은 그 첫걸음을 시작으로 몸과 구별되어, 변화무쌍하며, 아무것에도 매이지 않고, 묶이지 않은 배처럼 떠다니게 된다. 우리의 마음이 대자유 속에서 노닐 수 있는 방법을, 그리고 그 경지를 장자는 우리들에게 알려준다. The aim of this thesis is study focused on the human life in the “Inner Chapters” of the book of Zhuangzi. He was worried about life that was not threatened in a helpless world, and found the answer. This paper is intended to relight in the Inner Chapters of the book of Zhuangzi. The main text of this paper is “The Human World( )”, “Essentials for 人間世 Nurturing Life(養生主)”, “Symbols of Integrity Fulfilled(德充符)”, “Carefree Wandering(逍遙遊)”. In “the human world” chapter have looked at the side that has to accept the fate of “unavoidable” and the side of “mind” that is different from this. The second chapter of the “Inner Chapters” is titled “Essentials for Nurturing Life.” Pao Ding describes the process of mastering his skill, show Nurturing Life is complete. In “Symbols of Integrity Fulfilled” there are physically challenged people who will soon be able to confirm that they represent the inner faithfulness of virtue. Finally, “Carefree Wandering” expresses the ultimate state that human being can think to reach, that is, the great freedom of mind. It tells us how we can play in the great freedom of our hearts.

스페이스 마케팅의 집객적 요소를 적용한 국내 프리미엄 식품관 공간계획에 관한 연구

최동석(Choi, Dong-Seok),윤은경(Yun, Yean-Kyung) 한국실내디자인학회 2016 한국실내디자인학회 학술대회논문집 Vol.2016 No.10

South Korea’s Food hall in the past was focused on adjusting criteria of consumers to the choice of products and functions of the quality. However, as the structure of population, social, economic, and cultural changes occur, consumers’ various styles of consumption started to rise. And, in accordance, the age has changed to where consumers purchase products with value that suits their psychological, emotional state, and lifestyle. Accordingly, in addition to the premium products, premium Food hall is stimulating sensibility by providing experience has came in to the world. However, although many of the premium Food halls have set the slogan emphasizing consumer’s lifestyle and experience to, consumer’s degree of experience is at the paltry level. In this paper, by recognizing a need of new marketing techniques for consumers to feel experience and knowledge by having interactive relationship in space, it presents premium Food hall by applying strategic technique, Space Marketing.

[연료 및 윤활유부문] LPG 액상분무의 분열 및 혼합특성

최동석(Dong-Seok Choi),최재준(Jaejoon Choi),배충식(Choongsik Bae) 한국자동차공학회 2001 한국자동차공학회 춘 추계 학술대회 논문집 Vol.2001 No.11_1

The interaction between airflow and liquid phase LPG (Liquid Petroleum Gas) sprays was investigated in a steady flow system embodied in a wind tunnel to simulate the variety of flow inside intake port of LPG engines. The spray development in flowing fields \\ith the mean velocities of 5.4 and 42.4m/s was identified by spray visualization techniques such as Mie scattering and shadowgrnph. The microscopic visualization using a telescopic lens system was performed to investigate the shape and size of liquid droplets in the spray. The spray structure was identified into three phases: initial stage with a spiral vortex., end stage of injection recirculated with large-scale eddies, and stage after the end of injection governed by airflow. SMD at spray center (10mm downstream) was about 27?? and about 13% bigger than that at spray edge (12mm below nozzle hole). As air velocity increased, SMD at both positions became about 10% smaller

구동용 전동기의 출력특성에 대한 안전기준 부합성시험에 대한 연구

최동석(Dong-Seok Choi),박용성(Yongsung Park),이광범(Kwangbum Lee),권해붕(Haeboung Kwon),용기중(Geejoong Yong) 한국자동차공학회 2010 한국자동차공학회 부문종합 학술대회 Vol.2010 No.5

Compliance tests of electric motors for vehicle driving were performed to characterize power performance of the motors. Two different e-motors were used for testing the net power and the maximum 30 minutes power. One is a synchronous permanent magnet motor with water cooling. The other is an asynchronous induction motor with air cooling. According to the Korean safety regulation, electric power analysis was conducted and the temperature inside the motors was measured. It was found that temperature limit in each part was very important control factor and the speed or the torque control mode has to be selected as the type of the motors to be tested. Maximum 30 minutes power could be considered as the representative power of the motors.

직분식 가솔린 가시화 엔진의 성층연소 특성

최동석(Dong-Seok Choi),이용석(Yongseok Lee),최재준(Jaejoon Choi),배충식(Choongsik Bae) 대한기계학회 2002 대한기계학회 기타 간행물 Vol.2002 No.11