• Title/Summary/Keyword: 수직분사

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Spray Characteristics of Single and Double Liquid Jets in Crossflow (주류유동에서 단일 및 이중 수직분사 분무특성)

  • Yoon, Hyun-Jin;Hong, Jung-Goo;Park, Cheol-Woo;Lee, Choong-Won
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.36 no.5
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    • pp.495-501
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    • 2012
  • Spray characteristics of liquid jets in crossflow, which can be observed in the liquid jet injection system of a gas turbine or ramjet engine, were experimentally investigated. By measuring liquid jet penetration in the case of single orifice and double orifice injectors, the experimental formula for jet penetration was modified to consider penetration distances greater than that considered in a previous study. The changes in spray characteristics resulting from changes in the liquid jet and crossflow pressure, including SMD and jet disintegration, were carefully studied. Specifically, the jet penetration was measured for different injector shapes, and in the case of a double orifice injector, the penetration of the rear orifice jet was found to be greater by approximately 20% ($L_h$ = 4 mm) compared to that in the case of a single orifice injector because of the influence of the front orifice.

Combustion Characteristics of Hypersonic SCRamjet Engine (극초음속 스크램제트 엔진의 연소특성)

  • 원수희;정은주;정인석;최정열
    • Journal of the Korean Society of Propulsion Engineers
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    • v.8 no.1
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    • pp.61-69
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    • 2004
  • This paper describes numerical efforts to characterize the flame-holding and air-fuel mixing process of model SCRamjet engine combustor, where a hydrogen jet injected into a supersonic cross flow and in a cavity Combustion phenomena in a model SCRamjet engine, which has been experimentally studied at University of Queensland and Australian National University using a free-piston shock tunnel, was observed around separation region of upstream of the normal injector and inside of cavity. The results show that the separation region and cavity generates several recirculation zones, which increase the fuel-air mixing. Self ignition occurs in the separation-freestream and cavity-freestream interface.

Penetration and Breakup Characteristics of Pulsed Liquid Jets in Subsonic Crossflowse (아음속 수직분사제트에서의 가진 분무의 분무 특성연구)

  • Kim, Jin-Ki;Song, Jin-Kwan;Kim, Min-Ki;Hwang, Yong-Seok;Yoon, Young-Bin
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2007.11a
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    • pp.83-88
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    • 2007
  • The spray characteristics and liquid column penetration of steady and pulsed injection measurements have been experimentally studied using high speed camera in liquid jets injected into subsonic crossflow. The objectives of this research are to comparison the spray characteristics of steady injection with pulsed injection. Moreover. the effects of frequency are also studied. As the result, This research has been showed that pulsed injection has different penetration compared with steady injection.

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Time Evolution Characteristics of Transverse Injection into a Supersonic Crossflow (초음속 유동내 수직분사 유동의 시간 전개에 따른 특성)

  • Won, Su-Hee;Moon, Seong-Young;Jeung, In-Seuck;Choi, Jeong-Yeol
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2008.05a
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    • pp.343-346
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    • 2008
  • Unsteady 3D flowfields generated by transverse fuel injection into a supersonic mainstream are simulated with a DES turbulence model. Comparisons are made with experimental results in term of the temporal eddy position and eddy formation frequency. Results indicate that the DES model correctly predicts the convection characteristics of the large scale eddies. However, it is also observed that the numerical results slightly overpredict the eddy formation frequency.

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Characteristics of Dual Transverse Injection in Supersonic Flow Fields II-Combustion Characteristics (초음속 유동장 내 이중 수직분사의 특성에 관한 연구 II-연소특성)

  • Shin, Hun-Bum;Lee, Sang-Hyeon
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.30 no.6
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    • pp.61-68
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    • 2002
  • Combustion characteristics of dual transverse injection of hydrogen in supersonic air flows were studied using computational methods. Three-dimensional Navier-Stokes with a non-equilibrium chemical reaction model and the k-$\omega$ SST turbulence model were used. A parametric study was conducted with the variation of the distance between two injectors. Combustion characteristics of dual injection are very different from those of single injection. The combustion characteristics of two injection flows are very different from each other, and the ignition and combustion characteristics of the rear injection flow are strongly influenced by those of the front injection flow. The increase of the distance between two injectors up to a specific distance results in the increase of burning rate. However, the increase of the distance over the specific distance gives no increase of burning rate but makes more losses of stagnation pressure. From the results it can be stated that there exists a distance between two injectors for optimum combustion characteristics.

Effects of Orifice Internal Flow on Transverse Injection into Subsonic Crossflows: Cavitation and Hydraulic Flip (오리피스 내부 유동조건에 따른 수직분사제트의 분열특성에 대한 연구)

  • 안규복;김정훈;윤영빈
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2003.05a
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    • pp.72-75
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    • 2003
  • In this research, we focused on the effects of the orifice internal flow such as cavitation and hydraulic flip. The breakup characteristics such as the breakup length and trajectory were measured by changing the orifice diameter (d), the orifice length/orifice diameter (L/d), the injection pressure and the shapes (sharp and round) of orifice entrance to provide a lot of conditions of the orifice internal flow. It is found that cavitation bubbles that occur inside the sharp-edged orifice make the liquid jet ejecting from the orifice turbulent. In the orifices (L/d = 5), the hydraulic flip phenomenon is shown when the injection pressure is high. In case cavitation occurs it breaks up more earlier than that in case of non-cavitation. In case hydraulic flip occurs, since the area of the liquid jet becomes small, the breakup length is also small as that in case of cavitation. But the liquid column trajectories have a similar tendency irrespective of cavitation.

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Effects of Orifice Internal Flow on Transverse Injection into Subsonic Crossflows (아음속 유동장에 수직분사시 오리피스 내부유동 효과에 대한 연구)

  • 김정훈;안규복;윤영빈
    • Journal of the Korean Society of Propulsion Engineers
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    • v.7 no.1
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    • pp.28-39
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    • 2003
  • Effects of the orifice internal flow such as cavitation and hydraulic flip on transverse injection into subsonic crossflows have been studied. The liquid column breakup length and the liquid column trajectory were measured by changing the orifice diameter (d), the orifice length/orifice diameter (L/d), the injection pressure and the shapes (sharp and round) of orifice entrance, and were compared with previous results. It is found that cavitation bubbles, which occur inside the sharp-edged orifice, make the liquid jet very turbulent and especially in the orifices with L/d = 5 hydraulic flip appear as cavitation bubbles are emitted from the orifice. The breakup length is shorter as cavitation bubbles grows and hydraulic flip appears. However, the liquid column trajectories normalized by the effective diameter and the effective momentum ratio have a similar tendency irrespective of cavitation and hydraulic flip.

Multiphase Simulation of a Liquid Jet in a Lab-scale Ramjet Combustor (모형 램젯 연소기에서 액체제트의 다상유동 해석)

  • Oh, Jeong-Seog;Lee, Won-Nam;Lee, Jong-Geun;Santavicca, Dominique A.
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2010.11a
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    • pp.386-392
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    • 2010
  • The multiphase simulation of a liquid jet in a lab-scale ramjet combustor with a plain orifice type injector was studied with a commercial CFD tool, a FLUENT program. The objectives of the current study are to analysis the breakup characteristics of a hexane liquid jet in a cross flow and to derive the correlation between flow conditions and drag force coefficients in a test section. From the result of a numerical simulation, we concluded that a DPM and Realizable $k-{\varepsilon}$ model with an enhanced wall treatment were available to simulate the multiphase flow simulation. And the calculated distribution of a hexane vapor concentration was well-matched with experimental results.

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