• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 추계학술대회논문집B
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• pp.693-698
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• 2001

An experimental study was carried out with an aerated nozzle. This nozzle was well known that the performance of the atomization is better than other ones even though the supplied air pressure is lower than that of them. The purpose of this investigation is to provide the essential information of the aerated nozzle from the nozzle exit. The experimental work was performed in order to analyze the characteristics of the overall flow field from the nozzle exit. The 2-D PDPA system was used to acquire the data in the concerned region. The characteristics of the mean velocity distribution, half-width, and SMD were mainly analyzed. Also the correlation between turbulent kinetic energy and SMD was described with ALR.

• 한국분무공학회지
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• 제8권2호
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• pp.7-15
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• 2003

The effects of fuel density and fuel viscosity on spray characteristics were investigated under two different gas turbine fuels and various fuel supply pressure conditions through measurement of SMD, number density and volume flux by using PDPA system in dual orifice injector for gas turbine engines. In this study, we found out that the droplet size and spray structure are strongly depend on fuel density for dual orifice injector. The spray characteristics of high density fuel in dual orifice injector are similar with the characteristics of low density fuel in single orifice injector. The shear region between primary main fuel stream and secondary main fuel stream is examined in low density fuel condition but not exist in high density fuel condition, then this shear region is very important in quality of gas turbine spray. There are worth consideration for the effect of fuel density on spray characteristics in frontal device design to improve combustion efficiency.

• 한국자동차공학회논문집
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• 제12권6호
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• pp.23-29
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• 2004

This work was conducted to figure out the atomization characteristics of three types of bio-diesel fuels using a common-rail injection system. The process of spray development was visualized by using a spray visualization system composed of a Nd:YAG laser and an ICCD camera, The spray tip penetrations were analyzed based on the frozen images from the spray visualization system. On the other hand, the microscopic atomization characteristics such as the distributions of SMD and axial mean velocity were measured by using a phase Doppler particle analyzer system, It is revealed that the sprays of the bio-diesel fuels have larger SMD than that of diesel fuel mainly due to high viscosity of bio-diesel. Different characteristics of bio-diesel fuels were also measured in spray tip penetrations according to the fuels and mixing ration.

• 융복합기술연구소 논문집
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• 제3권2호
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• pp.51-56
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• 2013

This paper describes the atomization characteristics, as well as the velocity and size distribution, of DME spray based on common-rail injection system. To analyze the possibility of using DME fuel as an alternative fuel of diesel, spray atomization characteristics were investigated. For this investigation, two-dimensional phase Doppler analyzer system was used to obtain droplet size and velocity distribution simultaneously. Velocity and droplet size measurements were performed at various injection pressures. Results showed that increasing pressure from 25MPa to 50MPa leads to higher spray droplet velocities and smaller droplet diameter but injection pressure above 40MPa, no signifiant reduction was observed. With the droplet velocity and SMD comparison between diesel and DME fuel, it can be observed that DME has smaller SMD and droplet velocity due to its low surface tension.

• 한국분무공학회지
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• 제7권1호
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• pp.14-20
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• 2002

It is well known that the flow and spray characteristics is critical factor on the performance and emission of a direct injection diesel engine. So this study aims to investigate the interaction of flow and spray characteristics. At first, in cylinder flow distributions in swirl adaptor for 4-valve cylinder head of DI Diesel engine were investigated under steady conditions for different SCV angles mounted on the cylinder head with steady rig test and 2-D LDV. And the in-cylinder flow was quantified in terms of mean flow coefficient and swirl ratio/tumble ratio. It was found that the swirl ratio is controlled between 2.3 and 3.8. Then spray characteristics of the intermittent injection were investigated. PDA system was utilized for measurement of a droplet size and velocity. The analyses of the PDA results are carried out with Time Dividing Method. It was found that there is a correlation between the swirl flow and SMD. The droplet size and the velocity were nearly constant value with each SCV angle. And the swirl ratio is higher, SMD smaller. The swirl ratio was helpful factor to the atomization of droplet.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2007년도 제29회 추계학술대회논문집
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• pp.359-364
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• 2007

APU 가스터빈엔진의 연료분무특성을 연구하였다. 지상 및 고도 작동조건에 대한 연료분무특성 실험을 수행하여 APU 엔진의 실화 가능성을 검토하였다. 분무실험은 4개의 작동조건에 대하여 수행되었으며 각 조건은 지상 무부하 및 통합부하 조건과 고도 20,000 feet 무부하 및 통합부하에 대한 실험을 수행하였다. 분무특성은 PDPA를 이용한 입자의 크기 및 속도 측정과 레이저 빔을 이용한 가시화를 수행하였다. 연구결과 20,000 feet 무부하의 경우 입자의 크기가 100 ${\mu}m$정도이며 분무속도가 10 m/s로 낮아 화염안정성을 위한 개선이 필요할 것으로 판단된다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집D
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• pp.909-914
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• 2001

Fluid properties which are most commonly used to evaluate spray atomization characteristics, are important because they affect velocity and size distribution of droplets. The purpose of this study was to incorporate the significant characteristics in atomization process of industrial etching spray and how each of them affects the design of precise pressure-swirl nozzles. The experiment was carried out with different viscosity and density of fluid. The macro characteristics of liquid spray, such as the spray angle and shape were captured by PMAS and the micro characteristics of liquid spray, such as droplet size and velocity were obtained by PDA. The mean velocity and SMD of droplets were measured along axial and radial direction. It was found that the higher viscosity and density resulted in the larger SMD and the lower mean velocity of droplets.

• 대한기계학회논문집B
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• 제28권4호
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• pp.449-455
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• 2004

The objective of this study is to obtain the correlation between the spray characteristics and the etching characteristics for the optimization of etching system in the micro fabrication industry. The etching characteristics such as etching rate were measured under different conditions. The single spray characteristics such as droplet size and velocity were measured by PDA system. These were compared to the etching characteristics. The twin spray characteristics in the overlap region were analyzed to predict the effect of them on the etching characteristics with the pitch and also were compared to the single spray. The etching rate was increased in case of high spray pressure and in the region of spray center. It was found that the etching characteristics could be correlated with the single spray characteristics and the twin spray characteristics were correlated with the etching characteristics.

• 대한기계학회논문집B
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• 제28권1호
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• pp.109-117
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• 2004

The objective of this study is to investigate the effect of the spray characteristics on the etching characteristics for the optimization of etching process in the micro fabrication industry. The etching characteristics such as etching rate and etching factor were investigated under different etching conditions. To compare with the etching characteristic, the spray characteristics such as droplet size and velocity were measured by PDA system. The etching rate was increased in case of high spray pressure and in the region of spray center. The etching factor was increased with decrease in the distance from nozzle tip and increase in the etchant temperature. It was found that the spray characteristics were correlated with the etching characteristics.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 춘계학술대회
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• pp.2239-2244
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• 2003

A new stratified charge combustion system has been introduced and developed for GDI engines. Before this new GDI system, the stratified mixture was formed by a high pressure swirl injector. But, the special feature of new system is employed of a thin fan-shaped fuel spray formed by a slit type nozzle. Also, this system has been adopted a shell-shaped piston cavity. We made high pressure gasoline injection system and investigated the fan-shaped spray characteristics such as spray tip penetration, spray angle, SMD and velocities of droplets using PDPA(Phase Doppler Particle Analyzer) system and spray visualization system to obtain the concept of the new design and the fundamental data for the next generation GDI system. The experiment was performed at the injection pressures of 5 and 9MPa under the atmospheric condition.