• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 추계학술대회논문집B
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• pp.946-951
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• 2001

This experimental study is to investigate the intermittent spray characteristics of a pintle nozzle. High speed camera used in this expreiment with 9000fps. The factor, which controls the diesel spray, is the Injection pressure, ambient pressure and ambient temperature. In this paper, experiments were conducted free spray for the ambient pressure(3, 4, 5Mpa), nozzle Injection pressure(10, 14, 18MPa) and ambient temperature(293, 473K). With the higher opening pressure, the spray tip velocity and spray penetration increases while the spray angle decreases, On the other hand, With the higher ambient pressure, the spray angle increase while the spray tip penetration and spray tip velocity decrease. also, With the higher ambient temperature, the spray penetration decrease while the spray angle decrease.

• 한국자동차공학회논문집
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• 제5권3호
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• pp.128-136
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• 1997

Spray characteristics of a fuel injector have an important effect upon engine power and emission. Thus this study was investigated the spray characteristics of the intermittent injection using a gasoline fuel injector. Image processing system and PDA system were utilized for visualization of a spray behavior and measurements of a droplet size and velocity, respectively. Fuel injection duration was fixed with 3ms and injection pressure was varied such as 250kPa, 300kPa, 350kPa. for a high fuel injection pressure, spray tip arrival time was fluctuated at a vigorously disintegrated cross section. Axial velocity was linear correlated with fuel droplet size in the time interval of an injected main spray at spray downstream.

• 한국분무공학회지
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• 제22권4호
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• pp.169-174
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• 2017

The objective of this study was to verify the experimental and numerical results of spray evolution injected from different types of the nozzle-hole geometries. Spray visualization was taken by high speed camera under the different conditions. For the simulations of spray tip penetration, turbulence, evaporation and break-up model were applied K-zeta-f, Dukowicz and Wave model, respectively. Also, the prediction accuracy of spray tip penetration was increased by varying the spray cone angle. At the same time, the results of this work were compared in terms of spray tip penetration, and SMD characteristics. The numerical results of spray evolution process and spray tip penetration showed good agreement with experimental one.

• 한국분무공학회지
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• 제3권1호
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• pp.27-33
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• 1998

Correlations of drop size and velocity in a spray from the disintegration of liquid jet and liquid film from an internal mixing twin-fluid atomizer, were determined by phase Doppler method. The distribution pattern of Sauter mean diameter(SMD) in a spray was changed by a behavior of liquid flow. As smaller droplets became faster and slower easily by the surrounding conditions, the correlation between drop size and mean velocity was found to be varied as next 3 steps; firstly smaller droplets have a higher mean velocity at the area near atomizer, droplets have almost the same mean velocity and finally larger droplets have a higher mean velocity at the area far from an atomizer.

• 폴리머
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• 제31권3호
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• pp.215-220
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• 2007

전기분무에서의 전기유체 역학적 힘에 의한 표면 에너지의 조절은 간단한 입자 크기 조절, 단분산성, 높은 회수율, 그리고 약한 가공조건과 같은 이점을 제공할 수 있다. 이러한 이점은 단백질 약물전달체 제조에 적절할 것으로 예상되어, 본 연구에서 전기분무법을 이용하여 단백질 약물의 나노포집을 시도하였다. 모델 단백질인 알부민을 단축 혹은 동축 전기분무로 가공하였고 키토산, 폴리카플로락톤(PCL), 폴리 (에틸렌 글리콜) (PEG) 등이 포집물질로 사용되었다. 효율을 최대로 높이기 위해 분무액의 전기전도도, 유속, 전기포텐셜 구배의 거리 등과 같은 가공변수들이 조사되었다. 키토산 시스템에서 입자크기에 대한 공정 변수의 영향은 유속이 늦어질수록, 노즐과 집적부 사이의 거리가 가까울수록 입자 크기가 감소하는 것을 알 수 있었다. PCL 시스템에서는 단축 전기분무의 경우 유속이 늦어질수록, 동축 전기분무의 경우 내부와 외부 물질의 유속비가 클수록 입자 크기가 증가하는 것을 확인할 수 있었다. 전기분무 노즐에서 생성된 초기 입자들은 좁은 입자 크기 분포를 보였으나, 그것들이 집적부에 도달했을 때 입자들이 응집되는 경향이 있었다. 이러한 전기분무법에서 PCL, PEG, 키토산을 사용한 알부민의 효과적인 나노 포집은 12 kV 이상에서 성공적으로 이루어졌다.

• 한국분무공학회지
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• 제16권1호
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• pp.27-36
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• 2011

The impact force on the single and overlap region of twin spray was experimentally evaluated using visualization method in full cone type swirl nozzle spray. Visualization of spray was conducted to obtain the spray angle and breakup process. The photography/imaging technique, based on Particle Image Velocimetry (PIV) using high-speed camera, was adopted for the direct observation of droplet motion and axial velocity measurement, respectively. Droplet size was measured by Particle Motion Analyze System (PMAS). The purpose of this study is to provide fundamental information of spray characteristics, such as impact force, for higher etching factor in the practical wet etching system. It was found that the spray angle, axial velocity and impact force were increased with increasing the nozzle pressure while droplet size decreased with increasing the nozzle pressure. Droplet size increased as the distance from nozzle tip was decreased. The impact force of twin spray in the overlap region was about 63.29, 67.02, 52.41% higher than that of single spray at 40, 50 and 60 mm of nozzle pitch, respectively. Also, the nozzle pitch was one of the important factors in the twin spray characteristics.

• 폴리머
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• 제35권3호
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• pp.254-259
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• 2011

고분자 용액의 전기분무에서 금속 샘플 포집기들은 분무된 입자로부터 흔히 용매를 충분히 제거하거나 재분산이 가능한 분무 입자를 회수하는데 효과적이지 못하다. 단백질 약물의 캡슐화(encapsulation)를 위해 본 연구에서는 입자를 분산매(응고액제)의 층류 안으로 분무하는 새로운 전기분무시스템을 설계하였다. 캡슐화용 물질로 키토산과 폴리아크릴산이 사용되었다. 이 새로운 시스템을 사용하여 입자의 응집을 방지할 수 있었으며, 4~16 kV의 전압과 같은 유속에서 unimodal한 입도분포를 관찰할 수 있었다. 반면에 가한 전압이 평균 입자 크기에 미치는 영향은 크지 않았다.

• 한국분무공학회지
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• 제25권4호
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• pp.154-161
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• 2020

A single spray plume is the basic unit of the entire spray plume and is an important factor in understanding the spray characteristics. However, since the multi-hole GDI injector has a narrow spray angle, the superposition of the spray plumes occurs severely. Therefore, the spray uniformity and the spray atomization characteristics of a single spray plume were analyzed in this study using a single-hole GDI injector. Five single-hole GDI injectors with different nozzle hole diameters were used in the experiment. The uniformity of the spray was evaluated through the analysis of the spray pattern images. In addition, the atomization characteristics were compared using the diameter distribution of the spray droplets obtained using PDPA. As a result, the larger diameter of the nozzle hole, the less uniformity of the spray, and the injection pressure did not have a significant effect on the spray uniformity. It is judged that the surface roughness of the injector has a greater effect on spray uniformity than the diameter of the nozzle hole. Also, the size of the spray droplets increased sharply when the diameter of the nozzle hole was 230 ㎛.

• 한국자동차공학회논문집
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• 제6권5호
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• pp.199-210
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• 1998

The skill that utilizes atomization of the liquid has been widely used in the field of industry and engineering. Though there are dozens of methods to make atomization, the pressure type injection nozzle is frequently used in washing of parts, pastourization and painting because it has relatively simple system. This study is to reveal the characteristics of atomizing formed by three different types of the pressure type injection nozzle. We measured velocity and diameter of droplet to compare and analyze characteristic of each nozzle. In case of velocity, atomization of hollow-cone nozzle is irregular than others and change of radial direction is especially large. Atomization of flat nozzle is nearly uniform. In case of diameter, atomization of hollow-cone nozzle is increased rapidly, as measurement point become more distant from the center of nozzle. Atomization of flat nozzle has the most fixed magnitude. Accordingly, full-cone nozzle can be used irrespective of the form of subject and hollow-cone nozzle is proper to the occasion to spray large and smooth subject. Also, flat nozzle is proper to the occasion to spray a part of subject and long groove.

• Journal of Advanced Marine Engineering and Technology
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• 제34권5호
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• pp.645-652
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• 2010

본 연구의 목적은 다양한 분위기 압력 하에서 커먼레일 디젤인젝터를 통해 분사되는 비증발 디젤 분무특성에 관한 연구이다. 디젤분무의 거시적 특성으로 분무관통거리와 분무각을 음영사진과 이미지프로세싱으로 연구하였다. 수치해석은 상용 CFD프로그램인 AVL-FIRE를 사용하였다. 분열모델은 WAVE모델을 사용하였으며 표준 $k-{\varepsilon}$난류모델을 적용하였다. 분무각과 Zeuch법을 적용한 연료 분사율을 수치해석의 입력값으로 사용하였다. 분무관통거리를 실험값과 비교하여 좋은 결과를 얻었고 수치해석을 통하여 노즐팁 하류방향으로 분무의 각 구간별 액적입경분포를 알아보았다.