• Title/Summary/Keyword: Sauter

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Spray Characteristics of the Oxidizer-rich Preburner Injector in High Pressure Environments (로켓 산화제 과잉 예연소기용 분사기의 고압 분무특성 연구)

  • Yang, Joon-Ho;Choi, Seong-Man
    • Journal of the Korean Society of Propulsion Engineers
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    • v.12 no.2
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    • pp.48-56
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    • 2008
  • In the rocket preburner, oxidizer-rich combustion with liquid oxygen and kerosene is very challenging work. The key factor of stable flame is good mixing and that is controlled by the injector performance. We have studied spray characteristics of the oxidizer-rich rocket preburner injector in high pressure environments. The injector is composed of fuel orifices, oxidizer orifices and cooling skirt with liquid oxygen. By using this apparatus, we have taken photographs and measured Sauter mean diameter with changing ambient pressure from 0 to 30 kgf/cm2[g]. Droplet diameter is measured by the image processing technique. From the test results, we could understand spray characteristics of the oxidizer-rich preburner injector and this result could be applied to the development of the oxidizer rich preburner system.

A Study on the Particle Size and Velocity Profile on a Gasoline Port Injector Using a Phase Doppler Particle Analyzers (PDPA) (위상 도플러 입자 분석기(PDPA)를 이용한 가솔린 포트 인젝터의 입자 크기 및 속도 프로파일에 관한 연구)

  • KIM, HYOJIN;JO, HYUN;TONGCHAI, SAKDA;LIM, OCKTACKE
    • Journal of Hydrogen and New Energy
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    • v.28 no.3
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    • pp.300-307
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    • 2017
  • This study is to investigate particle size and velocity profile of gasoline port injector using Phase Doppler Particle Analyzer (PDPA). In this experiment, a GV 250 Delphi port injector used for motorcycles was used for liquid injection. The injector consists of four holes and has a static flow rate of 2.13 g/s. The fuel used in the injection was N-heptane, which is similar to gasoline, as an alternative fuel. The test fuel was injected at an atmospheric temperature of $20^{\circ}C$ and an open atmosphere of 1 atm. The injection time was 10 ms and the injection pressure was 3.5 bar in PDPA experiment. The experimental target position was fiexd at 30, 50 and 75 mm from the nozzle tip and data were collected for a total of 10,000 samples. The experimental results show that the length diameter (D10), the Sauter mean diameter ($D_{32}$), and the mean droplet velocity (MDV) are $45-54{\mu}m$, $99-115{\mu}m$ and 15-21 m/s, respectively.

The Spray Characterization Using Planar Imaging Technique (평면 이미지 기법을 이용한 분무 특성 해석)

  • Lee, Kyung-Jin;Jung, Ki-Hoon;Yoon, Young-Bin;Jeong, Kyung-Seok;Jeung, In-Seuck
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.24 no.1
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    • pp.93-101
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    • 2000
  • The characteristics of spray nozzle have been quantified with the measurement of fluorescence and Mie scattering images. To correct the attenuation of the incident light sheet, a sequential double-pass light sheet system and the geometrical averaging of two images was implemented. Quantitative mass flux distribution of spray was obtained from fluorescence image. 3-D image is reconstructed using 2-D radial images. Sauter mean diameter (SMD) distribution was determined using the ratio of fluorescence signal intensity and Mie scattering signal intensity and the values were quantified with PDP A data. The measurement of mass flux and SMD using planar imaging technique agee with PDP A data fairly well in the low density region. However, in dense region, there are significant errors caused by secondary scattering. It was found that the planar imaging technique provides many advantages over the point measurement technique, such as PDP A, and can be implemented for quantitative measurement, especially in low density region.

Stochastic Model Comparison for the Breakup and Atomization of a Liquid Jet using LES (LES 해석에서 액체제트의 분열에 대한 확률론적 분열 모델링 비교)

  • Yoo, YoungLin;Sung, Hong-Gye
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.45 no.6
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    • pp.447-454
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    • 2017
  • A three-dimensional two-phase large eddy simulation(LES) has been conducted to investigate the breakup and atomization of liquid jets such as a diesel jet in parallel flow and water jet in cross flow. Gas-liquid two-phase flow was solved by a combined model of Eulerian for gas flow and Lagrangian for a liquid jet. Two stochastic breakup models were implemented to simulate the liquid column and droplet breakup process. The penetration depth and SMD(Sauter Mean Diameter) were analyzed, which was comparable with the experimental data.

A Study on Atomization Characteristics of Gasoline Impinging Spray Using Glow plug (글로우플러그를 이용한 충돌분무의 미립화특성에 관한 연구)

  • 문영호;오영택
    • Transactions of the Korean Society of Automotive Engineers
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    • v.9 no.5
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    • pp.54-61
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    • 2001
  • It is reported that during the cold starting, especially in gasoline engine, the engine response and the effect of HC emission can be improved by prompting atomization and reducing the quantity of fuel adhered to the range of injector tip, inlet port, and inlet valve. The purposes of this study are to promote atomization of fuel before air-fuel mixture in the inlet port. In order to achieve its goal, the glow plug is to evaluate the feasibility of for the early fuel evaporator and the spray behavior characteristics of gasoline, injected on the surface of glow plug with room temperature(2$0^{\circ}C$) and high temperature(25$0^{\circ}C$) is to examine. Particle motion analysis system(PMAS) was used to measure the SMD and the dropsize distribution of impinging spray and free spray. The results of this experiment, evaporation rate of impinging spray was higher than that of free spray, and the higher evaporation rate win, the smaller peak dropsize was. Especially, during early spray SMD of impinging spray was still smaller than that of fee spray.

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The Influence of Liquid Atomization Models on Diesel Sprays (디젤분무에 대한 액체미립화모델들의 영향)

  • 이성혁;유홍선;홍기배
    • Transactions of the Korean Society of Automotive Engineers
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    • v.8 no.6
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    • pp.22-30
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    • 2000
  • The present article deals with comparisons of published liquid breakup models for diesel sprays to analyze the influence of breakup models on various spray parameters. The three different models tested in this study are the surface wave instability (Wave) model, the Taylor analogy breakup (TAB) model, and the drop drag model(DDM). The numerical results using these models are compared with several experimental data to assess the prediction capabilities of breakup models. Additional task in this study is to investigate effects of the breakup time constant in the Wave model on the spray parameters because the spray behavior is sensitive to the breakup time constant. It is seen that there is uncertainly about the breakup time constant indicating that the suitable acceptance of the constant is important, and the TAB model generally shows significant under-prediction of Sauter Mean Diameter(SMD). In addition, it may be indicated that differences between the DDM and Wave model are not significant, showing that the DDM may be suitable for air-assisted atomization rather than pressure atomization.

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Macroscopic Behavior and Atomization Characteristics of Dimethyl Ether (Dimethyl Ether(DME) 연료의 분무 거동 및 미립화 특성)

  • Suh, Hyun-Kyu;Park, Ji-Hong;Lee, Chang-Sik
    • Transactions of the Korean Society of Automotive Engineers
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    • v.15 no.5
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    • pp.30-37
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    • 2007
  • Dimethyl Ether(DME) is an alternative fuel for diesel engine, it is renewable and offers potential reductions in emissions. This work was conducted to figure out the macroscopic behavior and the atomization characteristics of DME using a common-rail injection system. The macroscopic behavior was visualized with the spray visualization system composed of a Nd;YAG laser and an ICCD camera. The atomization characteristics were investigated in terms of axial mean velocity, Sauter mean diameter(SMD) and droplet distributions obtained from a phase Doppler particle analyzer(PDPA) system. In this study, it was revealed that the macroscopic behavior and the atomization characteristics of DME are similar compared with commercial diesel fuel. However, DME fuel has a shorter spray tip penetration and a small SMD due to the effect of evaporation characteristics.

An Analysis on Spray Behavior of Liquid-thruster Injector through Pseudo-3D Distribution Measurement (준 3차원 공간분포 계측에 의한 액체 추력기 인젝터의 분무거동 해석)

  • Kim, Jin-Seok;Jung, Hun;Kim, Jeong-Soo;Kim, Sung-Cho
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2008.05a
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    • pp.141-144
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    • 2008
  • Atomization characteristics and spatial distribution of the spray emanating from an injector of liquid-propellant thruster are investigated by using dual-mode phase Doppler anemometry (DPDA). Spray characteristic parameters such as the mean velocity, Sauter mean diameter (SMD), and velocity fluctuation are measured at various locations along the spray axis as well as on the radial direction. Those data are quantified in radial profile and also used to scrutinize the correlation between diameter and turbulence intensity of spray droplets. For the better visual grasp, dynamic behavior of spray droplets along the spray stream is presented through the velocity vectors projected on the plane of geometric axis of nozzle orifice and radial coordinate.

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Measurement of Spray Characteristic Parameters for Inquiry into Small LRE-Injector's Injection Performance (소형 액체로켓엔진 인젝터의 분사성능 고찰을 위한 분무특성 매개변수 측정)

  • Jung, Hun;Kim, Jin-Seok;Kim, Jeong-Soo;Park, Jeong;Choi, Jong-Wook
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2009.05a
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    • pp.141-144
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    • 2009
  • An injector plays an important role in the process of an efficient combustion in liquid-rocket engines (LRE). This paper is focused on the injection performance of a small LRE-injector by employing the spray characteristic parameters made up of the velocity, Sauter mean diameter, and turbulence intensity. An experimental investigation is carried out with the aid of a dual-mode phase Doppler anemometry (DPDA) according to the injection pressure variation and along transverse axis, spatially. The Weber number and Reynolds number are used to characterize the atomization and turbulence nature of injector spray.

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An Experimental Study on Droplet Size Characteristics of Liquid Jets in Subsonic Crossflow (아음속 수직분사제트에서 액적크기 특성에 대한 실험적 연구)

  • Kim, Min-Ki;Song, Jin-Kwan;Kim, Jin-Ki;Hwang, Yong-Seok;Yoon, Young-Bin
    • Journal of ILASS-Korea
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    • v.12 no.2
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    • pp.115-122
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    • 2007
  • The spray characteristics and drop size measurements have been experimentally studied in liquid jets injected into subsonic crossflow. With water as fuel injection velocity, injection angle and atomize. internal flows were varied to provide of jet operation conditions. The injector internal flow was classified as three modes such as a non-cavitation flow, cavitation, and hydraulic flip flows. Pulsed Shadowgraph Photography measurement was used to determine the spatial distribution of the spray droplet diameter in a subsonic crossflow of air. And this study also obtains the SMD (Sauter Mean Diameters) distribution by using Planar Liquid Laser Induced Fluorescence technique. The objectives of this research are get a droplet distributions and drop size measurements of each condition and compare with the other flow effects. As the result, This research has been showned that droplet size were spatially dependent on air-stream velocity, fuel injection velocity, injection angle effects, and normalized distance from the injector exit length(x/d, y/d). There are also different droplet size characteristics between cavitation, hydraulic flip and the non-cavitation flows.

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