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정지원,차건종,김덕줄,Jung, Ji-Won,Cha, Keun-Jong,Kim, Duck-Jool 대한기계학회 2000 大韓機械學會論文集B Vol.24 No.10
The objectives of this study was to investigate the spray characteristics of single spray and twin spray in the overlap region such as mean axial velocity, mean radial velocity, mean droplet size and probability density function of droplet size. A phase doppler anemometer was used as the measurement system for droplet size and velocity. In case of single spray, injection pressure was varied from 0.2MPa to 0.7MPa. Mean axial velocity, mean radial velocity and droplet size were decreased as the distance below nozzle tip was increased. In case of twin spray, the spray characteristics were measured by varying the distance between two nozzles from 127mm to 155mm. In the overlap region, the boundary of the overlap region was determined by obtaining the distribution of mean axial and radial velocity. Droplet size was increased as the distance from nozzle tip was increased. It was found that the distribution of droplet size for twin spray in the overlap region was different to single spray.
송홍종,차건종,김덕줄,Song, Hong-Jong,Cha, Keun-Jong,Kim, Duck-Jool 대한기계학회 2000 大韓機械學會論文集B Vol.24 No.6
The emission in the exhaust gas from diesel engine is effected by the fuel spray characteristics. The spray of D.I. diesel engine impinges on a piston cavity and a cylinder wall. It is very important to know exactly the distribution and behavior of the spray inside cylinder. The objective of this study is to develop more accurate evaporation model. The EPISO code was used to analyze the flow characteristics in the engine. The Wakil model and the Faeth model are applied to the EPISO code to analyze the behavior of impinging spray. And also experimental and numerical analysis were carried out. The spray behavior characteristics were investigated by changing injection pressure, ambient pressure and temperature. The behavior of impinging spray was strongly effected by the change of ambient pressure and temperature. The effects of evaporation and rebounding droplet should be considered.
오리피스 형상에 따른 단공 노즐의 내부 가시화와 분무 특성
손종원 ( Jong Won Son ),차건종 ( Keun Jong Cha ),김덕줄 ( Duck Jool Kim ) 한국분무공학회 2002 한국액체미립화학회지 Vol.7 No.1
N/A The objective of this investigation was to obtain an excellent spray at the low injection pressure. When cavitation occurred in the nozzle hole, the atomization of the liquid jet enhanced considerably. In this experiments, a acrylic nozzle which was installed the gap and installed the bypass in the nozzle hole was used to enhance the atomization of the liquid jet at the low injection pressure. The liquid flow in the nozzle hole was photographed by a transmitted light using a micro flash. The spray angle was measured by macroscope images of PMAS and the Sauter mean diameter was measured by PDA system. The pressure of the nozzle hole was measured by pressure trasducer. It was found that enhanced atomization of the liquid jet at the low injection pressure was obtained by installing the gap and the bypass at the single hole nozzle.
디젤연소실에서 새로운 충돌분무 형성에 대한 수치적 고찰
류성목,차건종,김덕줄,박권하,Ryoo, Sung-Mok,Cha, Keun-Jong,Kim, Duck-Jool,Park, Kweonha 대한기계학회 1998 大韓機械學會論文集B Vol.22 No.11
The objective of this study is to establish geometric guidelines for design of impaction parts prepared for removing undesirable effects of fuel deposition on a wall in small direct-injection diesel engines. In order to get the guidelines a new wall geometry is introduced and assessed, which has a flat top and a slant edge. The size of the flat top and the angle of the slant edge are varied and tested in same chamber condition, then their effects on spray dispersions and drop sizes are discussed. The results show that the case of 3.0mm flat top and $60^{\circ}$ edge angle gives the best spray characteristics for a small combustion chamber in the test conditions chosen in this paper.
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.
[가솔린엔진부문] 직접 분사식 가솔린 기관의 실린더 내 분무의 거동
김한재(Han-Jae Kim),류경훈(Kyeong-Hun Ryun),최동석(Dong-Seok Choi),차건종(m Keun-Jong Cha),김덕줄(Duck-Jool Kim) 한국자동차공학회 2000 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
To achieve the requirement for high fuel economy and low emissions, the research of GDI engines is recently very brisk in the whole world. This study was performed to investigate the spray characteristics within cylinder of optically accessible direct-injected GOI engine. For this study, the conventional MPI, OOHC engine is modified into optically accessible GOI engine. The fluorescence images were captured using exciplex fluorescence method in a motoring engine. Four injection timing were set, namely, A TOC 90 °, BTOC 50 °and BTOC 70 °. The spray structure and penetration in optically accesible engine was influenced by tumble flow in cylinder.