• 제목/요약/키워드: Spray velocity

검색결과 535건 처리시간 0.018초

커먼레일 분사 시스템에서 DME-LPG 혼합연료의 분무거동에 관한 연구 (A Study on Spray Behavior of DME-LPG Blended Fuels in a Common-rail Injection System)

  • 김웅일;우승철;이창식;이기형
    • 한국분무공학회지
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    • 제20권1호
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    • pp.35-42
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    • 2015
  • This study is to investigate the spray behavior of DME-LPG blended fuels in common rail injection system for diesel engines. The visualization experiment was performed to analyze the macroscopic spray behavior of test fuels. In addition, the experiment using BOS(Background Oriented Schlieren) method is performed to compare liquid phase and gas phase. The test fuels are injected in high pressure chamber. The ambient pressure of high pressure chamber was formed by nitrogen gas. Spray tip penetration, spray cone angle and spray area were measured using high speed camera. SMD(Sauter Mean Diameter) and spray particle velocity were measured using the PDPA(Phase Doppler Particle Analyzer) system to analyze the microscopic properties of test fuels. The results of this experiment showed that spray tip penetration, spray cone angle and spray area of DME-LPG fuels are similar to those of DME fuel. When compared to results of experiment using BOS, significant differences of spray tip penetrations, spray cone angle and spray area are showed because of gas phase. The results of experiment using BOS method showed higher values. SMD of DME-LPG blended fuels is smaller than that of DME fuel. Velocity of DME-LPG blended fuels is faster than that of DME fuel.

직분식 가솔린기관 인젝터의 연료 분무 특성 (Fuel Spray Characteristics of GDI Injector)

  • 권상일;이창식
    • 한국연소학회:학술대회논문집
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    • 한국연소학회 2000년도 제21회 KOSCO SYMPOSIUM 논문집
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    • pp.194-201
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    • 2000
  • This paper is intended to analyze the macroscopic behavior and transient atomization characteristics of the high-pressure gasoline injector in direct-injection gasoline engine. The global spray behavior of fuel injector was visualized by shadowgraph technique. Time-resolved droplet axial and radial velocity components and droplet diameter were measured at many probe positions in both axial and radial directions by a two-component phase Doppler particle analyzer (PDPA). In order to obtain the influence of fuel injection pressure, the macroscopic visualization and experiment of particle measurement on the fuel spray were investigated at 3,5 and 7 MPa of injection pressure under different surrounding pressure in the spray chamber. The results of this work show that the fuel injection pressure of gasoline injector in GDI engine has influence upon the mean droplet diameter, mean velocity of spray droplet, the spray tip penetration, and spray width under the elevated ambient pressure.

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포트 분사 연료 인젝터의 분무 구조에 관한 연구 (An Study on the Spray Structure of Fuel Port Injectors)

  • 이창식;이기형;전문수;손강호;박종순
    • 한국분무공학회지
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    • 제3권3호
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    • pp.42-48
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    • 1998
  • This study describes the spray structure of gasoline port injectors by using phase Doppler particle analyzer(PDPA) and particle motion analysis system(PMAS). The characteristics of fuel spray such as the spray penetration, spray angle and breakup processes were obtained by PMAS and the droplet size and mean velocity were measured by PDPA system. Pintle type and two-hole type injectors were used as gasoline port fuel injectors under various injection pressures. The effect of injection pressure on the droplet mean diameter and axial mean velocity of droplet were investigated under the various injection conditions. In addition the comparison of breakup processes for the two types of injectors was also conducted. It Is shown that pintle type injector has smaller droplet size than that of two-hole type injector.

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가솔린 화재의 소화를 위한 수분무의 특성에 관한 실험적 연구 (Characteristics of Water Spray for Extinguishment of Gasoline Pool Fire)

  • 장용재;김명배;김유
    • 한국화재소방학회논문지
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    • 제9권2호
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    • pp.10-16
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    • 1995
  • This study discribes characteristics of water spray for extinguishment of gasoline fire. Experiments are carried out for the gasoline pool fire nth the atomizing nozzles. Droplet size, spray pressure, amount of water which reaches the flame base and velocity of water spray are measured to find extinguishment conditions. Air entrainment due to the water spray and extinguishing process of gasoline fire by water spray are visualized. Boundary conditions of water spray for extinguishment of gasoline pool fire is quantitatively shown. As the result of experiments, it is found that the velocity of entrainment air and sprayed water are almost same and the water droplets size having small diameter under 40$\mu\textrm{m}$ can not extinguish the fire because too small droplets does not reach the fuel surface.

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Full Cone Type 스월노즐에서 단일분무와 이중분무의 중첩영역에 대한 충격력 평가 (Evaluation of the Impact Force on the Single Spray and Overlap Region of Twin Spray in Full Cone Type Swirl Nozzle)

  • 김태현;성연모;정흥철;김덕줄;최경민
    • 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.

디젤 충돌 분무의 발달 과정 및 내부 유동 특성 (Internal Structure and Velocity Field of the Impinging Diesel Spray on the Wall)

  • 전문수;서현규;박성욱;이창식
    • 한국분무공학회지
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    • 제10권3호
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    • pp.1-8
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    • 2005
  • The purpose of this study is to investigate the internal structure of the impinged diesel spray at various experimental conditions. To examine the effect of various factors on the development of a diesel spray impinging on the wall, experiments were conducted at the various Injection pressures, wall distances from the nozzle tip and angles of wall inclination. The PIV system consists of a double pulsed Nd:YAG laser was utilized to analyze the internal flow structure of impinged diesel sprays. The velocity fields from the PIV system were compared with the results measured by the phase Doppler particle analyzer(PDPA)system. The results show that internal flow pattern of the impinged spray was similar with the results from the PDPA system. The radial velocity of the impinged spray was increased with the increase in the injection pressure and near the nozzle-wall distance. The generation of vortex was also promoted with the Increase in angles of wall inclination.

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발사체 충격 방식을 사용한 초음속 액체 제트의 과도 분무 형상에 관한 연구 (Transient Spray Structures of Supersonic Liquid Jet Injected by Projectile Impact Systems)

  • 신정환;이인철;김희동;구자예
    • 한국분무공학회지
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    • 제17권2호
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    • pp.86-93
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    • 2012
  • The effects of projectile impact system on the transient spray characteristic which is supersonic liquid tip velocity were studied by experimentally. Supersonic liquid jets were generated by impact of a high speed projectile driven by a Two-stage light gas gun. A high speed camera and schlieren optical system were used to capture the spray structures of the supersonic liquid jets. In a case of nozzle assembly Type-A, expansion gases accelerate a projectile which has a mass of 6 grams from 250 m/s at the exit of the launch tube. Accelerated projectile collides with the liquid storage part, then supersonic liquid jets are injected with instantaneous spray tip velocity from 617.78 m/s to 982.54 m/s with various nozzle L/d. However, In a case of nozzle assembly Type-B which has a heavier projectile (60 grams) and lower impact velocity (182 m/s), an impact pressure was decreased. Thus the liquid jet injected at 210 m/s of the maximum velocity did not penetrate a shock wave and fast break-up was occurred. Pulsed injection of liquid column generated second shock wave and multiple shock wave.

Experimental Study on Spray Etching Process In Micro Fabrication of Lead Frame

  • Jung, Ji-Won;Choi, Gyung-Min;Kim, Duck-Jool
    • Journal of Mechanical Science and Technology
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    • 제18권12호
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    • pp.2294-2302
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    • 2004
  • The objective of this study is to obtain detailed information for the micro fabrication of lead frames by applying spray technology to wet etching process. Wet etching experiments were performed with different etching parameters such as injection pressure, distance from nozzle tip to etched substrate, nozzle pitch and etchant temperature. The characteristics of single and twin spray were measured to investigate the correlation between the spray characteristics and the etching characteristics. Drop size and velocity were measured by Phase-Doppler Anemometer (PDA). Four liquids of different viscosity were used to reveal the effects of viscosity on the spray characteristics. The results indicated that the shorter the distance from nozzle tip and the nozzle pitch, the larger etching factor became. The average etching factor had good positive correlation with average axial velocity and impact force. It was found that the etching characteristics depended strongly on the spray characteristics.

노즐 내부 스월러각과 스월실 형상비 변화가 분무특성에 미치는 영향 (Effect of Internal Swirler Angle and Swirl Chamber Aspect Ratio of Nozzle on Spray Characteristics)

  • 김영진;정홍철;정지원;김덕줄
    • 한국분무공학회지
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    • 제8권4호
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    • pp.39-45
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    • 2003
  • The Objective of this study is to investigate the effect of internal swiller angle and swirl chamber aspect ratio of nozzle on spray characteristics for application of spray system in micro fabrication process. The macro-spray characterictics such as the spray angle and breakup process were obtained by photographs illustrating atomization. The micro-spray characteristics such as droplet size and axial velocity were measured by using PDA with swirler angle and swirl chamber aspect ratio. The swiller angles were $13.5^{\circ},\;27^{\circ},\;and\;40.5^{\circ}$. The swirl chamber aspect ratios were 1.2, 1.6, and 2.0. It was found that the smaller swirl chamber aspect ratio was, the larger axial velocity and drop size were.

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Atomization Characteristics and Prediction Accuracy of LISA-DDB Model for Gasoline Direct Injection Spray

  • Park, Sung-Wook;Kim, Hyung-Jun;Lee, Ki-Hyung;Lee, Chang-Sik
    • Journal of Mechanical Science and Technology
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    • 제18권7호
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    • pp.1177-1186
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    • 2004
  • In this paper, the spray atomization characteristics of a gasoline direct-injection injector were investigated experimentally and numerically. To visualize the developing spray process, a laser sheet method with a Nd :YAG laser was utilized. The microscopic atomization characteristics such as the droplet size and velocity distribution were also obtained by using a phase Doppler particle analyzer system at the 5 ㎫ of injection pressure. With the experiments, the calculations of spray atomization were conducted by using the KIVA code with the LISA-DDB breakup model. Based on the agreement with the experimental results, the prediction accuracy of LISA-DDB breakup model was investigated in terms of the spray shapes, spray tip penetration, SMD distribution, and axial mean velocity. The results of this study provides the macroscopic and microscopic characteristics of the spray atomization, and prediction accuracy of the LISA-DDB model.