• Title/Summary/Keyword: Spray angle

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An Investigation of Methanol and Methanol Blended Sprays Using Laser Scattering Images

  • Park, Wook;Park, Byung-Chul
    • Journal of Mechanical Science and Technology
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    • v.15 no.12
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    • pp.1699-1710
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    • 2001
  • The characteristics of methanol and methanol blended (M85) sprays were investigated under atmospheric conditions at various temperature, ranging from on-vaporizing to vaporizing ambient conditions (298∼353 K). From laser scattering images, the macroscopic characteristics of the spray, such as the spray tip penetration and the spray angle, were determined. Entropy concept was introduced to represent homogeneity and PIV analysis was adopted to determine the fluid dynamic information at each location of the spray. The correlation between entropy and vorticity strength enabled us to find their relations. The effect of ambient composition, mainly of viscous effect as affected by CO$_2$levels, was investigated using PIV and entropy analysis. Spray width and entropy value were found to tend to decrease at increased CO$_2$levels.

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A Study on the Spray Characteristics of Swirl Injectors Using ANSYS Fluent (ANSYS Fluent를 이용한 와류형 분사기의 분무특성 연구)

  • Yoon, Wonjae;Lee, Bom;Ahn, Kyubok
    • Journal of ILASS-Korea
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    • v.22 no.4
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    • pp.159-168
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    • 2017
  • Numerical studies on the spray characteristics of closed-type and open-type swirl injectors were conducted using ANSYS Fluent. By changing injection pressures, discharge coefficient and spray angle were calculated using the Reynolds stress BSL turbulent model. The numerical results were compared with previous experimental data to examine their accuracy. For a closed-type swirl injector, spray angles matched well with experimental results and discharge coefficients showed approximately 8% differences. On the contrary, discharge coefficients of an open-type swirl injector were similar with experimental result but its spray angles presented around 15% differences. Though the numerical results were not perfectly consistent with experimental data, it is thought that they could be sufficiently used for analyzing spray characteristics, specially which is hard to be measured from experiments. Numerical simulation with different turbulent models was also performed to examine their effects on the numerical results.

ANALYSIS OF THE SUITABLE INJECTION PRESSURE FOR DIESEL INJECTION WITH HIGH PRESSURE

  • JEONG D. Y.;LEE J. T.
    • International Journal of Automotive Technology
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    • v.6 no.2
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    • pp.87-93
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    • 2005
  • Spray patterns were visualized using the shadowgraph method, and the droplet size and velocity were measured using PDPA for high-pressure injections up to 2,600 bars. The spray pattern and spray characteristics, such as penetration, spray width, spray angle, droplet size, injection duration, and droplet velocity, were investigated to determine the suitable injection pressure. Spray penetration, width, angle, and velocity increased continuously up to 2,600 bars with the injection pressure in a high-pressure region. The rate of improvement of the above spray characteristics, however, declined rapidly, when the injection pressure reached 2,000 bars. The injection duration and droplet size generally decreased with the increase in the injection pressure, while the rate of improvement decreased abruptly after 2,000 bars. Consequently, the improvement rate of the spray characteristics became blunt at over 2,000 bars. This means that the suitable injection pressure is around 2,000 bars.

Study on the Spray Characteristics of Liquid/Liquid Pintle Injector by Opening Distance (액체/액체 핀틀 분사기의 개도에 따른 분무특성 연구)

  • Yoon, Wonjae;Ahn, Jonghyeon;Ahn, Kyubok;Yoon, Hosung
    • Journal of the Korean Society of Propulsion Engineers
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    • v.25 no.3
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    • pp.14-25
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    • 2021
  • An experimental study was conducted on the spray characteristics of the pintle injector by opening distance. The discharge coefficient of the pintle injector was investigated and the spray angle was measured by taking the spray image by test conditions. As a result of the measurement of the discharge coefficient, it was confirmed that the change in the discharge coefficient of the outer injector was not significant over the experimental conditions, but the change in the discharge coefficient of the inner injector was decreased as the flow rate increased. Measurement of the spray angle showed that the change in the spray angle was not significant in the conditions under which the spray was fully developed, but the spray was not fully developed at low flow rates. This confirmed the possibility of thrust control using the pintle injector.

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

  • Kim, T.H.;Sung,, Y.M.;Jeong, H.C.;Kim, D.J.;Choi, G.M.
    • Journal of ILASS-Korea
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    • v.16 no.1
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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.

Diesel Spray Developement from VCO nozzles for High Pressure Direct-Injection (VCO노즐에서 고압으로 분사되는 디젤분무의 특성)

  • 강진석;배충식
    • 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.

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A Study on the Spray, Combustion, and Exhaust Emission Characteristics of Dimethyl-ether (DME) by Experiment and Numerical Analysis (Dimethyl-ether (DME) 연료의 분무, 연소 및 배기 특성에 관한 실험 및 수치해석적 연구)

  • Park, Su-Han;Kim, Hyung-Jun;Lee, Chang-Sik
    • Journal of ILASS-Korea
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    • v.15 no.1
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    • pp.31-37
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    • 2010
  • The aim of this work is to investigate the spray and combustion characteristics of dimethyl-ether (DME) at various injection conditions. The spray characteristics such as spray tip penetration and spray cone angle were experimentally studied from the spray images which obtained from the spray visualization system. Combustion and emissions characteristics were numerically investigated by using KIVA-3V code coupled with Chemkin chemistry solver. From these results, it revealed that DME spray had a shorter spray tip penetration and wider spray cone angle than that of diesel spray due to the low density, low surface tension, and fast evaporation characteristics. At the constant heating value condition, DME fuel showed higher peak combustion pressure and earlier ignition timing, because of high cetane number and superior evaporation characteristics. In addition, the combustion of DME exhausted more $NO_x$ emission and lower HC emission due to the active combustion reaction in the combustion chamber. The result shows that DME had a little soot emission due to its molecular structure characteristics with no direct connection between carbons.

An Investigation on the Spray Characteristics of DME Common Rail Fuel Injection System with Variation of Ambient Pressure (분위기 압력변화에 따른 DME 커먼레일 연료 분사 시스템의 분무 특성에 관한 연구)

  • Lee, Se-Jun;Oh, Se-Doo;Jeong, Soo-Jin;Lim, Ock-Taeck
    • Transactions of the Korean Society of Automotive Engineers
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    • v.20 no.2
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    • pp.90-97
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    • 2012
  • It is investigated of the DME spray characteristics about varied ambient pressure and fuel injection pressure using the common rail fuel injection system when the nozzle holes diameter is varied. The common rail fuel injection system and fuel cooling system is used since DME has compressibility and vaporization in atmospheric temperature. The fuel injection quantity and spray characteristics were measured. The spray was analyzed of spray shape, penetration length, and spray angle at the six nozzle holes. The 2 types injector were used, the one was 0.166 mm diameter the other one was 0.250 mm diameter. The ambient pressure which is based on gage pressure was 0 MPa, 2.5 MPa, and 5 MPa. The fuel injection pressure was varied by 5 MPa from 35 MPa to 70 MPa. When using the converted injector, compared to using the common injector, the DME injection quantity was increased 127 % but it didn't have the same heat release. Both of the common and converted injector had symmetric spray shapes. In case of converted injector, there were asymmetrical spray shapes until 1.2 ms, but after 1.2 ms the spray shape was symmetrical. Compared with the common and converted injector, the converted injector had shorter penetration length and wider spray angle than the common injector.

An Experimental Investigation on Spray Behavior of Biodiesel and DME on Blended Ratio in High Temperature and Pressure Ambient Conditions (고온 고압 분위기 조건에서 바이오 디젤과 DME의 혼합비에 따른 분무특성에 관한 연구)

  • Bang, Seung-Hwan;Chon, Mun-Soo;Lee, Chang-Sik
    • Journal of ILASS-Korea
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    • v.15 no.1
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    • pp.17-24
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    • 2010
  • The objective of this work is to analyze the macroscopic behavior of spray and injection characteristics on the DME blended biodiesel at different mixing ratios by using spray visualization and injection rate measurement system. The spray images were analyzed to a spray tip penetration, a spray cone angle and a spray area distribution at various mixing ratio of DME by weight. The influence of different injection pressure and ambient pressure on the fuel spray characteristics are investigated for the various injection parameters. In order to analyze the injection characteristics of test fuels, the fuel injection rate is measured at various blending ratio. The variation of viscosity of the blended fuel by the mixing of DME fuel shows the improved effect of spray developments. Also, it was found that the injection quantities of high blended ratio were larger than that of lower blended fuel. Also, higher blending fuel showed a faster evaporation than that of mixing ratio of test fuel because kinetic viscosity was changed by blending ratio.

The Effects of Injector Nozzle Geometry and Operating Pressure Conditions on the Transient Fuel Spray Behavior

  • Koo, Ja-Ye
    • Journal of Mechanical Science and Technology
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    • v.17 no.4
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    • pp.617-625
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    • 2003
  • Effects of Injector nozzle geometry and operating pressure conditions such as opening pressure, ambient pressure. and injection pressure on the transient fuel spray behavior have been examined by experiments. In order to clarify the effect of internal flow inside nozzle on the external spray, flow details Inside model nozzle and real nozzle were alto investigated both experimentally and numerically. for the effect of injection pressures, droplet sizes and velocities were obtained at maximum line pressure of 21 MPa and 105 MPa. Droplet sizes produced from the round inlet nozzle were larger than those from the sharp inlet nozzle and the spray angle of the round inlet nozzle was narrower than that from the sharp inlet nozzle. With the increase of opening pressure, spray tip penetration and spray angle were increased at both lower ambient pressure and higher ambient pressure. The velocity and size profiles maintained similarity despite of the substantial change in injection pressure, however, the increased injection pressure produced a higher percentage of droplet that are likely to breakup.