• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2017년도 제48회 춘계학술대회논문집
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• pp.892-895
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• 2017

대형 가스터빈 연소기 구성품인 단일 압력선회식 연료분사기(Pressure swirl simplex liquid injector)를 설계, 분무특성 및 성능을 시험을 통해 평가하였다. 공급 압력 대비 분무 유량을 측정하여 설계점 기준 분무유량과 비교하였으며 섀도우그래프(Shadowgraph)를 통해 분무가시화이미지를 기록, 분무의 형상을 정성적으로 파악하고 분무각을 측정하였다. 시험 결과 동일한 공급압력 대비 측정된 분무유량은 설계점 기준 유량과 거의 일치하여 설계 및 제작의 정합성이 확인되었으며 섀도우그래프 이미지를 통해 연료분사기의 분무형상을 파악하고 설계 의도된 분무각이 나타남을 확인할 수 있었다. 이를 기반으로 향후 PDA(Phase Doppler Anemometry)를 통한 분무측정을 통해 보다 구체적인 연료 분사기의 분무 성능 및 특성을 파악할 수 있을 것으로 기대된다.

• 한국분무공학회지
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• 제6권2호
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• pp.16-21
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• 2001

This paper describes the macroscopic behavior and atomization characteristics of the high-pressure gasoline swirl injector in direct-injection gasoline engine. The global spray behavior of fuel injector was visualized by shadowgraph technique. The atomization characteristics of gasoline spray such as mean diameter and mean velocity of droplets were measured by the phase Doppler particle analyzer system. The macroscopic visualization and experiment of particle measurement on the fuel spray were investigated at 7 and 10 MPa of injection pressure under different spray cone angle. The results of this work show that the geometry of injector was more dominant over the macroscopic characteristics of spray than the fuel injection pressure and injection duration. As for the atomization characteristics, the increase of injection pressure resulted in the decrease of fuel droplet diameter and the atomization characteristics differed as to the spray cone angle. The most droplets had under $25{\mu}m$ diameter and for the large droplets(upper $40{\mu}m$) as the spray grew the atomization presses were very slow. Comparison results between the measured droplet distribution and the droplet distribution functions revealed that the measured droplet distribution is very closed to the Normal distribution function and Nukiyama-Tanasawa's function.

• 한국분무공학회지
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• 제7권1호
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• pp.29-35
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• 2002

This study describes the external spray characteristics of deflector nozzle such as the breakup procedures of liquid sheet, spray angle, breakup length and bubble behaviors of spray at deflector nozzle. In order to visualize the spray behaviors shadow graphy technique were used. According to the increase injection pressure, deveopment of the spray passes through the dribbling, distoted jet, closed bubble due to the contraction by form a conical sheet like as the simplex swirl atomizer. As trying the analysis of the ratio of bubble length and width it was found that the ratios is comparable. Spray cone angle was nearly $90^{\circ}$.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2002년도 학술대회지
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• pp.291-294
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• 2002

This study describes the external spray characteristics of deflector nozzle such as the breakup procedures of liquid sheet, spray angle, discharge coefficient and bubble behaviors of spray and SMD at deflector nozzle. In order to visualize the spray behaviors shadow graphy technique were used. According to the increase of injection pressure, development of the spray passes through the dribbling, distoted jet, closed bubble due to the contraction by surface tension forces, the bubble opens into hollow tulip shape, and the curved surface straightened to form a conical sheet like as the simplex swirl atomizer. Spray cone angle was nearly 90 deg. Variations of SMD were examined in order to describe the dependency of SMD on the injection pressure and orifice diameter. The shape of deflector and oriffice diameter had an effect on the discharge coefficient.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.3467-3472
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• 2007

The effects of the wall geometry on the spray-wall impingement process of a hollow-cone fuel spray emerging from a high-pressure swirl injector of the Gasoline Direct Injection (GDI) engine were investigated by means of a numerical method. The ized Instability Sheet Atomization (LISA) & Aerodynamically Progressed Taylor Analogy Breakup (APTAB) model for spray atomization process and the Gosman model were applied to model the atomization and wall impingement process of the spray. The calculation results of spray characteristics, such as a spray development process and a radial distance after wall impingement, compared with the experimental ones by the Laser Induced Exciplex Fluorescence (LIEF) technique. It was found that the radial distance of the cavity angle of 90$^{circ]$ after wall impingement was the shortest and the ring shaped vortex was generated near the wall after spray-wall impingement process.

• 오토저널
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• 제12권5호
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• pp.76-84
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• 1990

To study diesel fuel spray behavior, an experimental study was undertaken to investigate injection characteristics in vary ing back pressure and atomization mechanism in a non-evaporating diesel spray. Generally, injection characteristics is the curve of fuel flow plotted against time. The area under this curve is equal to the total quantity of fuel discharged for one injection. The method that measures rate of injection is long tube-type fuel rate indicator. Diesel spray injected into a quiescent gaseous environment under high pressure is observed by taking high speed camera by the focused shadow photographs. The results show that, at the start of injection, as the injected fuel rushes into the quiescent atmosphere the spray angle becomes large. Finally the spray stabilizes at a constant cone angle. Spray penetration length increases with the injection pressure.

• 대한기계학회논문집B
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• 제31권12호
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• pp.971-978
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• 2007

A spray-wall impingement process of a hollow-cone fuel spray from the high-pressure swirl injector in the Gasoline Direct Injection (GDI) engine were experimented and calculated at various wall geometries. The Linearized Instability Sheet Atomization (LISA) & the Aerodynamically Progressed Taylor Analogy Breakup (APTAB) model and the Gosman model were applied to model the breakup and the wall impingement process of the hollow-cone fuel spray. The numerical modelings were implemented in the modified KIVA code. The calculation results of spray characteristics, such as a spray development process and a radial distance after wall impingement, compared with the experimental results by the Laser Induced Exciplex Fluorescence (LIEF) technique. The droplet size distribution and the ambient gas velocity field, which are generally difficult to obtain by the experimental methods, were also calculated and discussed. It was found that the radial distance after wall impingement and Sauter Mean Diameter (SMD) decreased with increasing a cavity angle.

• 한국분무공학회지
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• 제6권2호
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• pp.9-15
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• 2001

The internal flow characteristics of a gasoline direct injector have been studied to improve fuel economy and reduce exhaust emissions. Computational Fluid Dynamics (CFD) is used to examine the internal flow of the GDI with the purpose of designing the optimum geometry of the injector. This study tests orifice length, cone angle, swirl angle, orifice diameter and needle lift. The results show that optimum sizes of the orifice length, cone angle, swirl angle, orifice diameter and needle lift are 0.8mm, $140^{\circ},\;120^{\circ},\;80mm\;and\;70{\mu}m$, respectively. The size of the lift does not affect the formation of the air core signficantly near the tip of the needle compared to the ball-type needle. The vena contracta phenomenon near the orifice inlet can be released by smoothing the edge.

• 한국추진공학회지
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• 제20권4호
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• pp.68-76
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• 2016

본 연구는 이원추진제 추력기의 핵심부품에 대한 성능평가의 일환으로, 기체메탄/액체산소를 추진제로 사용하는 스월 동축형 인젝터의 리세스 길이 및 분사압력에 따른 분무특성 파악을 목표로 하였다. 분무형상은 슐리렌 가시화 기법을 이용하여 획득하였고, 슐리렌장치는 광원, 오목거울, 초고속카메라 등으로 구성된다. 내부 인젝터에 의한 액체 분무의 경우 hollow cone 형상을 확인하였으며, 내부 인젝터 오리피스 길이의 증가와 함께 스월강도 감쇠의 영향으로 분무각은 줄어들었다. 기체-액체를 함께 분사할 때, 분무각은 리세스 길이가 증가함에 따라 외부혼합영역에서 증가하지만, 내부혼합영역에서는 작아졌는데, 액체분무 분사 압력의 높고 낮음에 무관하다는 사실을 확인하였다.

• 한국가시화정보학회지
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• 제6권1호
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• pp.59-65
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• 2008

Distribution of spray was measured. Optical Line Patternator (OLP) was used to measure the planar distribution of the spray from a swirl-coaxial type injector. Ambient pressure was varied and injection pressure was fixed in experiment. As ambient pressure increased, spray distribution was changed from hallow cone to solid cone shape, and spray angle was decreased. Limitation in measuring dense spray was found at high ambient pressure condition.