• Title/Summary/Keyword: Taylor cone

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The Analysis of Two-phase Flow in a Lean Direct Injection Gas-turbine Combustor (희박연료 직접분사(Lean Direct Injection) 가스터빈 연소기의 이상유동 분석)

  • Lee, Kyobin;Kim, Jong-Chan;Sung, Hong-Gye
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.47 no.3
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    • pp.204-211
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    • 2019
  • The analysis on two-phase flow in a Lean Direct Injection(LDI) combustor has been investigated. Linearized Instability Sheet Atomization(LISA) and Aerodynamically Progressed Taylor Analogy Breakup(APTAB) breakup models are applied to simulate the droplet breakup process in hollow-cone spray. Breakup model is validated by comparing penetration length and Sauter Mean Diameter(SMD) of the experiment and simulation. In the LDI combustor, Precessing Vortex Core(PVC) is developed by swirling flow and most droplets are atomized along the PVC. It has been confirmed that all droplets have Stokes number less than 1.0.

Modeling of Wall Impingement Process of Hollow-Cone Fuel Spray according to Wall Geometry (벽면 형상에 따른 중공 원추형 분무의 벽 충돌 과정 모델링)

  • Shim, Young-Sam;Choi, Gyung-Min;Kim, Duck-Jool
    • Proceedings of the KSME Conference
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    • 2007.05b
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    • pp.3467-3472
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    • 2007
  • The effects of the wall geometry on the spray-wall impingement process of a hollow-cone fuel spray emerging from a high-pressure swirl injector of the Gasoline Direct Injection (GDI) engine were investigated by means of a numerical method. The ized Instability Sheet Atomization (LISA) & Aerodynamically Progressed Taylor Analogy Breakup (APTAB) model for spray atomization process and the Gosman model were applied to model the atomization and wall impingement process of the spray. The calculation results of spray characteristics, such as a spray development process and a radial distance after wall impingement, compared with the experimental ones by the Laser Induced Exciplex Fluorescence (LIEF) technique. It was found that the radial distance of the cavity angle of 90$^{circ]$ after wall impingement was the shortest and the ring shaped vortex was generated near the wall after spray-wall impingement process.

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Spray and Evaporation Characteristics of DME fuel at the High pressure and temperature (고온 고압하에서의 DME 연료 분무 및 증발 특성)

  • Kim, Hyung-Jun;Suh, Hyun-Gyu;Lee, Chang-Sik
    • Journal of ILASS-Korea
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    • v.12 no.2
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    • pp.101-107
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    • 2007
  • The purpose of this study is to analyze spray and evaporation characteristics of DME fuel at the high pressure and temperature. For the numerical analysis of dimethyl ether(DME) fuel spray characteristics, hybrid breakup model was applied to the DME spray and its breakup process. In order to obtain experimental results for comparison with the predicted ones, the visualization of the spray evolution process was executed by using a Nd:YAG laser. Also, the numerical investigation was conducted by the two hybrid models for primary and secondary breakup of the DME spray. The primary breakup model was used the Kelvin-Helmholtz(KH) breakup model. In the secondary breakup process, Rayleigh-Taylor(RT) and Drop Deformation Breakup(DDB) model was applied. The results of this study provide the macroscopic characteristics of the spray such as spray tip penetration and cone angle, and prediction accuracy of the two hybrid model.

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Analysis of Dual Combustion Ramjet Using Quasi 1D Model (준 1차원 모델을 적용한 이중연소 램제트 해석)

  • Choi, Jong Ho;Park, Ik Soo;Gil, Hyun Young;Hwang, Ki Young
    • Journal of the Korean Society of Propulsion Engineers
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    • v.17 no.6
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    • pp.81-88
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    • 2013
  • The component based propulsion modeling and simulation of an dual ramjet engine using Taylor-Maccoll flow equation and quasi 1-D combustor model. The subsonic and supersonic intake were modeled with Taylor-Maccoll flow having $25^{\circ}$ cone angle, the gas generator which transfers a pre-combustion gas into supersonic combustor was developed using Lumped model, and the determination of the size of nozzle throat of a gas generator was described. A quasi 1-D model was applied to model a supersonic combustor and the variation of temperature and pressure inside combustor were presented. Furthermore, the thrust and specific impulse applying fuel regulation by pressure recovery ratio and equivalence ratio were derived.

Measurement of Size Distributions of Submicron Electrosprays Using a Freezing Method and an Image Processing Technique (냉각법 및 영상 처리기법을 이용한 서브마이크론 정전분무 액적의 크기분포 측정)

  • Ku, Bon-Ki;Kim, Sang-Soo;Kim, Yu-Dong
    • Proceedings of the KSME Conference
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    • 2001.06e
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    • pp.100-106
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    • 2001
  • The size distributions of electrospray droplets from the Taylor cone in cone-jet mode are directly measured by using a freezing method and a transmission electron microscope (TEM) image processing technique. These results are compared with the data obtained by an aerodynamic size spectrometer (TSI Aerosizer DSP). The use of glycerol seeded with NaI and a freezing method make it possible to sample droplets with their original sizes preserved. Since pictures of droplets are taken with TEM with very low vapor pressure of the solution, evaporation is suppressed by freezing. For liquid flow rates below 1 nl/sec, the measured droplet diameters by the TEM image processing technique and the aerosizer are in the range of 0.25 to $0.32{\mu}m$ and 0.30 to $0.40{\mu}m$, respectively. Comparing the TEM data with the aerosizer measurements, it has been revealed that the TEM image processing technique can afford more accurate values of droplet size distributions in the submicron range of 0.1 to $0.4{\mu}m$.

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A Study on Atomization and Wall Impingement Process of Hollow-Cone Fuel Spray (중공 원추형 연료 분무의 미립화 및 벽 충돌 과정에 대한 연구)

  • Shim, Young-Sam;Choi, Gyung-Min;Kim, Duck-Jool
    • Transactions of the Korean Society of Automotive Engineers
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    • v.14 no.4
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    • pp.132-138
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    • 2006
  • Numerical analysis about atomization and wall impingement process of hollow-cone fuel spray is performed by a modified KIVA code with hybrid model. The atomization process is modeled by using hybrid breakup model that is composed of Linearized Instability Sheet Atomization(LISA) model and Aerodynamically Progressed Taylor Analogy Breakup(APTAB) model. The Gosman model, which is based on the droplet behaviors after impingement determined by experimental correlations, is used for spray-wall impingement process. The LIEF technique was used to compare the results with those of experiment. The calculations and experiments are carried out at the ambient pressures of 0.1 MPa and 0.5 MPa and the ambient temperature of 293K. It was found that the calculated results show satisfactory agreement with experimental ones.

Numerical Study on Wall Impingement Process of GDI Spray According to Wall Cavity Angle (벽면 캐비티 각에 따른 GDI 분무의 벽 충돌 과정에 대한 수치적 연구)

  • Shim, Young-Sam;Kim, Duck-Jool;Choi, Gyung-Min
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.31 no.12
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    • pp.971-978
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    • 2007
  • A spray-wall impingement process of a hollow-cone fuel spray from the high-pressure swirl injector in the Gasoline Direct Injection (GDI) engine were experimented and calculated at various wall geometries. The Linearized Instability Sheet Atomization (LISA) & the Aerodynamically Progressed Taylor Analogy Breakup (APTAB) model and the Gosman model were applied to model the breakup and the wall impingement process of the hollow-cone fuel spray. The numerical modelings were implemented in the modified KIVA code. The calculation results of spray characteristics, such as a spray development process and a radial distance after wall impingement, compared with the experimental results by the Laser Induced Exciplex Fluorescence (LIEF) technique. The droplet size distribution and the ambient gas velocity field, which are generally difficult to obtain by the experimental methods, were also calculated and discussed. It was found that the radial distance after wall impingement and Sauter Mean Diameter (SMD) decreased with increasing a cavity angle.

Supersonic Flow Air Data Acquisition Algorithm Using Total Pressure Sensors (전압력센서를 적용한 초고속 유동데이터 산출 알고리즘)

  • Choi, Jong-Ho;Lee, Jae-Yoon;Yoon, Hyun-Gull;Lim, Jin-Shik
    • Journal of the Korean Society of Propulsion Engineers
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    • v.15 no.5
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    • pp.60-65
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    • 2011
  • The development of an air data acquisition algorithm has been described in the supersonic flow at the preliminary design stage with pressure data acquisition device composed of major three total pressure sensors and two static pressure sensors which are installed on the surface of a cone type supersonic inlet. Through this algorithm, Mach number, angle of attack and sideslip angle can be very easily derived with simple interpolation algorithm and predefined data tables. The available range of Mach number is 1.6 to 4.0, angle of attack, $-12^{\circ}$ to $12^{\circ}$ and sideslip angle, $-12^{\circ}$ to $12^{\circ}$. In preliminary design stage, the data tables applied to the developed algorithm are constructed with data driven by Taylor Maccoll equation. The present algorithm would be useful to get supersonic flow air data for the various aerial vehicles and their flight tests.

Measurement of Size Distributions of Submicron Electrosprays Using a Freezing Method and an Image Processing Technique (냉각법 및 영상 처리기법을 이용한 서브마이크론 정전분무 액적의 크기분포 측정)

  • Gu, Bon-Gi;Kim, Sang-Su;Kim, Yu-Dong;Lee, Sang-Yong
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.25 no.10
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    • pp.1400-1407
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    • 2001
  • The size distributions of electrospray droplets from the Taylor cone in cone-jet mode are directly measured by using a freezing method and a transmission electron microscope (TEM) image processing technique. These results are compared with the data obtained by an aerodynamic size spectrometer (TSI Aerosizer DSP). The use of glycerol seeded with NaI and a freezing method make it possible to sample droplets with their original sizes preserved. Since pictures of droplets are taken with TEM with very low vapor pressure of the solution, evaporation is suppressed by freezing. For liquid flow rates below 1 nl/sec, the measured droplet diameters by the TEM image processing technique and the aerosizer are in the range of 0.25 to 0.32 m add 0.3B to 0.40m, respectively. Comparing the TEM data with the aerosizer measurements, it has been revealed that the TEM image processing technique can afford more accurate values of droplet size distributions in the submicron range of 0.1 to 0.4m.

Characteristics of Water Surface Discharge due to Water Conductivity (수증 전도도 변화에 따른 수표면 방전의 특성)

  • 박승록;김진규;김형표
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.18 no.2
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    • pp.44-48
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    • 2004
  • A silent type ozone generator using water surface electrode was proposed. And it was investigated experimentally that a variation of water conductivity affected to water surface discharge. Important factors affecting to water surface discharge are ions in discharge space and ions and polarized molecules in water and so on. In this study, It was intended to change the characteristics of discharge by controlling the number of ions in water. The number of ions in water could be controlled by changing the water conductivity. Water conductivity was controlled by quantity of inserted NaCl to distilled water. At this time, current-voltage characteristics and characteristics of ozone generation quantity were investigated in each case. As a result, when NaCl was inserted in distilled water, more stable discharge was generated. As the quantity of NaCl was increased, discharge starting voltage could be lowered.