• 한국추진공학회지
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• 제3권4호
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• pp.44-50
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• 1999

Unlike impinging Quadlet injector(OOOF type)에 대한 혼합효율, 혼합특성속도, 혼합특성속도효율을 연소성능을 예측하기 위해 비연소 실험을 통하여 구하였다. 모의 추진제는 물($H_2$O)와 케로신($CH_{1.97}$)을 사용하였고, 혼합상관인자로써 산화제, 연료 분류의 운동량비를 사용하였다. 인젝터 분무특성을 파악하기 위해 오리피스(orifice) 각 hole에 대한 유량계수, 분무형상, 질량분포 획득이 수행되어졌다. 연구 결과, 침투깊이는 혼합효율, 혼합특성속도, 혼합특성속도 효율에 영향을 미침을 알 수 있었다. 또한, 혼합효율 및 혼합특성속도 효율은 MR=1.67(TMR=2.5)에서 87%로 최대값을 가지며 산화제 과잉상태보다 연료 과잉상태에서 더 큰 감소율을 보였다.

• 한국추진공학회지
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• 제24권6호
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• pp.126-142
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• 2020

본 연구에서 액체-액체 핀틀 분사기가 적용된 연소장치의 연구개발 사례 조사를 통해 핀틀 분사기 및 연소장치의 설계 기초자료를 제공하고자 하였다. 자료 분석 결과로 엔진 추력에 따른 연소실 및 핀틀 분사기 규격, 고효율 분사기의 형상을 확인할 수 있었다. 그밖에 핀틀팁 열손상 방지 기구와 소재, Face-shutoff 핀틀 분사기 구현 방법, 중심추진제 선정 기준 등을 정리하여 초기 핀틀 분사기 적용 연소실 설계의 기초자료로 활용하고자 한다.

• 한국분무공학회지
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• 제8권3호
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• pp.10-18
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• 2003

In this paper, experimental study on the wan impingement spray of the common-rail diesel injector is performed. To examine the effect of various factors on the development of spray impinging on the wall, experiments were conducted at the various injection pressures. ambient pressures, wan distances from the injector tip, wall temperatures, and angles of wall inclination. The behaviors of the impingement spray ate visualized by using laser sheet methods and a ICCD camera. It is shown that the spray path penetration of the wall impingement spray increases with the increase of injection pressure, wall distance. wall temperature, wall angle. On the other hand the spray path penetration of the wan impingement spray decreases with the increase of ambient pressure.

• 한국분무공학회지
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• 제8권3호
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• pp.19-26
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• 2003

In this study, experimental study on atomization characteristics of the fuel spray impinging on the wall was at different wall distances and angles of wall inclination. The fuel injection system was composed based on the common rail system. and the injection signal was synchronized by the delay generator. The atomization characteristics of the injected spray were analyzed in terms of the SMD and velocities which were measured by using the phase Doppler particle analyzer system. It is revealed that the free spray is atomized actively above 50mm form the injector tip. In the cases of the impinged spray, the 5MD and velocity of the impinged spray are smaller than those of the free spray. The impinged spray has the maximum near the 35mm of the radial distance from the injector axis, and the atomization performance is enhanced with the decrease of the wall distance.

• 한국자동차공학회논문집
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• 제6권5호
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• pp.174-181
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• 1998

Experimental and analytical studies are presented to characterize the break-up mechanism and atomization processes of the intermittent- impinging-type nozzle. Gasoline jets passing through the circular nozzle with the outlet diameter of 0.4mm and the injection duration of 10ms are impinged on each other. The impingement of fuel jets forms a thin liquid sheet, and the break-up of the liquid sheet produces liquid ligaments and droplets subsequently. The shape of liquid sheets was visualized at various impinging velocities and angles using the planer laser induced fluorescence (PLIF) technique. Based on the Kelvin-Helmholtz wave instability theory, the break-up length of liquid sheets and the droplet diameter are obtained by the theoretical analysis of the sheet disintegration. The mean diameter of droplet is also estimated analytically using the liquid sheet thickness at the edge and the wavelength of the fastest growing wave. The present results indicate that the theoretical results are favorably agreed with the experimental results. The size of droplets decreases after the impingement as the impinging angle or the injection pressure increase. The increment of the injection pressure is more effective than the increment of the impinging angle to reduce the size of droplets.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2005년도 제25회 추계학술대회논문집
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• pp.384-394
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• 2005

Important characteristics of impinging sprays intersected by a strongly convective gaseous cross flows were experimentally investigated. The breakup processes due to different Weber and Reynolds numbers of liquid and gas streams were visually examined with quantitative measurements of breakup lengths, penetration heights, and droplet sizes. Snapshot images and spay data evidenced that, at lower jet Reynolds number the breakup processes portrays the atomization profiles similar to typical column breakup of single orifice jet. At higher jet Reynolds numbers, disintegration of jet stream is significantly expedited by strong momentum transported from strongly convective gaseous stream. The breakup length and penetration height decreased as the convective flow increase. From the bottom the wall up, the SMD measured the centerline increase. The maximum SMD appeared the top of the SMD distribution

• 한국연소학회:학술대회논문집
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• 한국연소학회 2012년도 제45회 KOSCO SYMPOSIUM 초록집
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• pp.5-7
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• 2012

This study presents relations between the time lag and interaction index of the impinging-jet injectors using time lag model in a model chamber. To analyze the response of the flame, 5% amplitude of oxidizer velocity is artificially perturbed at a resonance frequency. At the mixing point of fuel and oxidizer, which determines the characteristic length, the relationship between velocity perturbation and heat release rate is quantified by combustion parameters of interaction index and time lag. As the improved method to apply the time-lag, the method using the average velocity obtained from numerical results is suggested.

• 한국분무공학회지
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• 제2권4호
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• pp.22-28
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• 1997

In this paper an experimental study of a spray created by two impinging jets is presented utilizing a novel two-reference-beam double-pulse holographic technique. Visualization of the overall spray pattern as well as measurements on the size and velocity of the droplets were performed with the special emphasis on the effect of physical properties of liquids. The overall spray pattern clearly revealed the inherent wave nature In the disintegration process of this type of atomization. The structure of liquid elements near the impingement point is indicative of the mechanisms of the disintegration process. Surface tension plays an important role in the droplet size without any noticeable effect on the spray pattern, whereas viscosity affects the structure without any significant effect on the droplet sire. The droplet velocities were not affected by liquid properties.

• 한국분무공학회지
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• 제29권2호
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• pp.75-82
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• 2024

In this study, the thickness of the liquid sheet formed by a splash plate nozzle at low jet velocities was measured by the direct contact method. The spatial distribution characteristics of the sheet thickness in the radial and circumferential directions, and the effects of jet velocity and liquid viscosity were analyzed. The wavy surface was observed for low viscosity water, but not for high viscosity glycerol solutions. The sheet thickness decreased as the circumferential angle or the distance from the impinging point increased. The sheet thickness increased as the liquid viscosity increased. Comparison with the theoretical predictions for two impinging jets showed some differences from the measurement results.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2009년도 제33회 추계학술대회논문집
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• pp.217-220
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• 2009

본 연구는 케로신-LOX를 연료와 산화제로 하는 액체로켓엔진의 가스발생기용 스월 동축형 인젝터의 리세스 길이에 따른 분무특성 파악을 목표로 하였다. 리세스 길이에 따른 두 추진제의 혼합 형태가 내부 혼합, 팁 혼합, 외부 혼합 등으로 분류되고, 인젝터 외부의 분무안정성에 영향을 미치므로 분무특성과 큰 연관성을 가진다.