• Transactions of the Korean Society of Automotive Engineers
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• v.8 no.3
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• pp.28-36
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• 2000

Spray characteristics of diesel fuel injection is one of the most important factors in diesel combustion and pollutant emissions especially in HSDI (High Speed Direct Injection) diesel engines where the interval between the onset of combustion and the evaporation of atomized fuel is relatively short, An investigation into various spray characteristics from different holes of VCO(Valve Covered Orifice) nozzles was performed and its results were compared to standard sac nozzle. The global characteristics of spray, including spray angle, spray tip penetration, and spray pattern were measured from the spray images which were frozen by an instantaneous photography with a spark light source. For better understanding of spray behavior, SMD of the fuel sprays from multi hole nozzles were measured with back light imaging while the sprays from the other holes are covered by a purpose-built nozzle cap. The investigation manifestly reveals the different spray patterns at the beginning of injection produced by VCO nozzles can be identified as three distinct types with their own macroscopic and microscopic characteristics, while macroscopic non-uniformity disappears at 0.9∼1.0ms from the start of injection.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2007.04a
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• pp.97-101
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• 2007

The spray characteristics of the oxidizer-rich preburner are investigated. From the PDPA measurement, droplet SMD of $210{\mu}m$ and droplet axial velocity of 38 m/s are measured at 100 mm distance from the nozzle tip on the fuel pressure of $25kgf/cm^2$ and oxidizer pressure of $10kgf/cm^2$. The droplet velocity is decreased with the axial distance and the oxidizer spray makes dominant effect on the combined spray characteristics of the oxidizer-rich preburner injector.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.04a
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• pp.16-19
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• 2011

An experimental study on the spray characteristics of Gas-centered swirl coaxial injectors(GCSCI) for high-performance staged combustion rocket engines has been carried out using cold flow tests. In this study, water and gaseous nitrogen are used as working fluids and a back-lit photography technique with image processing for the measurements of spray characteristics. Our study is focused on the effect of injector geometries like as gap thickness of liquid nozzle and gas nozzle and momentum flux ratio for fundamental understanding of the injectors.

• Journal of ILASS-Korea
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• v.27 no.4
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• pp.173-180
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• 2022

Cooling fog is being used in various parts of society such as fine dust reduction, cleanliness, and temperature drop. Cooling fog has the advantage of low flow rate and ease of use compared to other spray systems. In the case of cooling fog, it was confirmed that the injection angle increased as the pressure increased and the nozzle diameter increased. In this study, the minimum injection angle was 33.61 degrees and the maximum injection angle was 107.38 degrees. It was confirmed that the larger the nozzle diameter and the smaller the pressure, the larger the droplet size. In addition, it was confirmed that the Sauter Mean Diameter (SMD) increased along the X and Y axis directions. It was confirmed that the size of the droplet decreases as it approaches the nozzle tip due to the characteristics of the nozzle design factor.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.11a
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• pp.202-206
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• 2009

We studied the spray characteristics of the high-speed rotating fuel injection system. The diameter of in-line injection orifices are varied from 1mm to 5mm and the number of in-line injection orifices are varied from 3 to 12. Droplet size, velocity and spray distribution were measured by the PDPA(Phase Doppler Particle Analyzer) system and spray was visualized. From the test results, the liquid column generated from the injection orifice is mainly controlled by the rotational speeds. Also diameter of injection orifices and number of injection orifices have influence on the diameters of droplet. Consequently, we find out that the basic mechanism of controlling the droplet size is the liquid film thickness in the injection orifice.

• Journal of Energy Engineering
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• v.7 no.1
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• pp.17-23
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• 1998

A simplified experiment was performed to figure out the atomization characteristics of highly viscous liquid of rice-bran oil by applying ultrasonic energy to improve the atomization of spray droplets. A spray system, an ultrasonic system, and three kinds of pintle-type nozzles(pin-edge angle: 5 , 10 , 15 ) were manufactured. To investigate the effects of ultrasonic energy on the atomization of a highly viscous liquid, a phase doppler particle analyzer was used for the measurement and calculation of spray droplets data. Nozzle opening pressures were chosen of 3 levels, i.e, 10, 13, 16 MPa. As a result, it could be concluded that the ultrasonic energy was effective to improve the spray atomization when applied to the fuel by means of 3 different nozzles because of the effects of the liquid fuel cavitation and relaxation between molecules caused by ultrasonic energy. The improvement rate of the spray atomization by the ultrasonic spray atomization by the ultrasonic spray compared with the conventional spray was about 10% increase in the case of pintle type nozzles. With the increase of pin-edge angles the distribution lines by nozzle opening pressures are declined for both conventional and ultrasonic sprays. This means that the increase of the pin-edge angle improves the atomization of sprays.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2003.02a
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• pp.83-89
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• 2003

붐방제기는 분무관에 일정한 간격으로 노즐이 설치되어 있으며 목표물 바로 위에서 농약을 직접 살포할 수 있다. 따라서 비산의 위험성이 적고 작업폭이 넓기 때문에 포장능률도 높은 장점이 있다. 또한 방제작업에 영향을 미치는 방제속도, 살포폭, 노즐 배출량, 노즐 압력 등을 최적으로 유지할 수 있는 자동제어 시스템을 채택할 수 있어 최적량의 농약을 균일하고 유효하게 살포할 수 있다. (중략)

• Proceedings of the Korean Institute of Industrial Safety Conference
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• 2000.11a
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• pp.118-123
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• 2000

화재에 대한 소화방법으로서는 점화원의 냉각, 산화제 농도의 감소에 의한 화염의 질식 및 제거소화와 부촉매를 이용한 소화법이 있다. 이중 냉각소화방법은 주로 물을 사용하여 화재를 진압하고 있으나, 유류화재와 전기화재 등에서는 물보다 할론소화약제가 효과적으로 사용되어 왔다. 그러나 할론 등 CFC 계통의 소화약제는 환경오염물질을 내포하며, 지구온난화지수와 오존파괴지수 등이 높아 전세계적으로 그 사용이 중단되고 있다. 이에 대한 대체 기술의 하나로 최근에 관심이 고조되기 시작한 소화기술은 분무 노즐을 이용한 미세물분무(water mist) 소화설비이다.(중략)

• Journal of the Korean Society of Industry Convergence
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• v.3 no.1
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• pp.37-42
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• 2000

액체 분무가 벽면의 평평한 면에 충돌할 때의 거동에 대해 실험을 통하여 조사하였다. 각 분사노즐과 벽면까지의 거리 그리고 분사 속도에 있어서 충돌점에서의 액체 액막의 비산 거동과 평면에서의 액막의 흐름에 대하여 관찰하였다. 충돌점에서 비산하는 액적의 비산율을 정량적으로 측정하였다. 분사속도가 증가에 의해 충돌 거동은 5개의 영역으로 분류되며, 분사속도가 증가하면 비산율도 증가하게 된다. 또한, 충돌거리가 분무의 분열점보다 길때의 분사량의 약 반 정도가 비산하게 되는 결과가 얻어졌다.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.19 no.1
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• pp.40-45
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• 1983

The paper describes an experimental investigation of axisymmetric diesel spray and flame which is held in rapid compression machine (RCM) with electromagnetic single injection nozzle. The axisymmetric diesel spray and flame are taken with high speed photograph and analysis it with image processor. The data presented include fuel concentration of spray, flame temperature, soot concentration of flame in axial and radial direction at a moment and compared it with each other.