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충돌 분무의 성장에 미치는 분사압과 배압의 영향에 관한 연구
차건종,서경일,김덕줄,Cha, Geon-Jong,Seo, Gyeong-Il,Kim, Deok-Jul 대한기계학회 1997 大韓機械學會論文集B Vol.21 No.11
This study investigated the effects of pressure on the growth of an impinging spray. We obtained the frozen images which were scattered by Nd ; YAG laser light (pulse width : 7 ns) using synchronization circuit made in the laboratory. For an impinging spray a growth of the penetration length was progressed with increase of the injection pressure but an ambient pressure restrained its growth. The effect of an ambient pressure on penetration was larger than that of an injection pressure. The pressure ratio had an effect on the penetration growth rate. The thickness growth rate depended on both the injection pressure and the ambient pressure compositively. A lower injection pressure or a higher ambient pressure was required for spatial distribution of impinging 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.
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.
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.
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.
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.