• Title/Summary/Keyword: 수직분사

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Combustion and Spray Characteristics of Jet in Crossflow in High-Velocity and High-Temperature Crossflow Conditions (고온고속기류 중에 수직 분사되는 액체제트의 연소 및 분무특성)

  • Yoon, Hyun Jin;Ku, Kun Woo;Kim, Jun Hee;Hong, Jung Goo;Park, Cheol Woo;Lee, Choong Won
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.37 no.1
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    • pp.67-74
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    • 2013
  • A jet in a crossflow (JICF) has been extensively studied because of its wide applications in technological systems, including fuel injection into a ram-combustor. However, in the case of insufficient mixing performance of the liquid jet into the crossflow, the flame in a ram-combustor is unstable. In this study, the nonuniform flame and combustion instabilities due to lack of mixing performance were experimentally investigated. By performing correlations to predict the penetration height and break-up point, the spray and mixing characteristics of JICF have been studied. In particular, the improved correlations of penetration height are proposed in two distinctive domains depending on the X/d location of the crossflow.

Combustion Characteristics Study using Hyper-mixer in Low-enthalpy Supersonic Flow (하이퍼 혼합기를 사용한 저엔탈피 초음속 유동장 내연소 특성 연구)

  • Kim, Chae-Hyoung;Jeung, In-Seuck
    • Journal of the Korean Society of Propulsion Engineers
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    • v.17 no.6
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    • pp.75-80
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    • 2013
  • In this study, a forced ignition method with a plasma jet torch is studied in Mach 2 laboratory scaled wind-tunnel. The hyper-mixer is used as a mixer. For two normal injection cases, the one is collided against a wedge plate of the hyper-mixer and the other is directly injected into the cold main flow. For the first case, the hyper-mixer disperses the injected fuel, leading to the mixing enhancement. Furthermore, the fuel-air mixture is provided into the plasma hot gas, which enhances the combustion performance. However, the direct injection into the main flow method spends amount of fuel without ignition in the cold supersonic flow. In the end, for the forced combustion, it is important to supply the fuel-air mixture into the heat source.

An Experimental Study on the Trajectory Characteristics of Liquid Jet with Canted Injection Angles in Crossflow (수직분사제트에서 다양한 분사각도의 분무궤적 특성에 대한 실험적 연구)

  • Kim, Min-Ki;Song, Jin-Kwan;Hwang, Jeong-Jae;Yoon, Young-Bin
    • Journal of the Korean Society of Propulsion Engineers
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    • v.12 no.6
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    • pp.38-47
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    • 2008
  • The liquid column and spray trajectory have been experimentally studied in liquid jets injected into subsonic crossflow. With water as fuel injection velocity, injection angle were varied to provide of jet operation conditions. The Pulsed Shadowgraph Photography and Planar Liquid Laser Induced Fluorescence technique was used to determine the injection characteristics in a subsonic crossflow of air. And the mainly objectives of this research was to get a empirical formula of liquid column and spray region trajectory with forward and reversed injection of air stream. As the result, This research has been shown that each trajectories were spatially dependent on air-stream velocity, fuel injection velocity, various injection angle, and normalized injector exit diameter. Furthermore, the empirical formula of liquid column trajectories has been some different of drag coefficient results between forward and reversed angled injection.

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

  • Kim, Min-Ki;Song, Jin-Kwan;Kim, Jin-Ki;Yoon, Young-Bin
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2006.11a
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    • pp.59-63
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    • 2006
  • A direct photograph measurement technique was used to determine the spatial distribution of the spray droplet diameter in subsonic crossflow and it also obtain that SMD distribution by using PLLIF technique. The injector internal flow was classified as three modes such as a normal, cavitation, and hydraulic flip. The objectives of this research are getting a droplet distribution and drop size measurement of normal flow and compare with the other flow effects. Although the study showed visually that drop size were spatially dependent of Air-stream velocity, fuel injection velocity, and normalized distance from the injector exit length.(x/d, y/d) There are also difference characteristics between cavitation, hydraulic flip and the normal flow.

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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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The regime map for the direct contact condensation of steam vertically injected through a mini nozzle (미세노즐을 통해 수직분사된 수증기의 직접접촉응축 영역도)

  • Lee, Soo-Kwan;Bae, Song-Hyo;Kim, Moo-Hwan
    • Proceedings of the KSME Conference
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    • 2004.11a
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    • pp.1075-1079
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    • 2004
  • Steam was vertically discharged into water through mini nozzles of various diameters (d=0.115, 0.520, 1.55mm). The condensation was observed and categorized into several types of condensation regimes for each of the nozzles. Compared with the regimes in the previous researches, the regimes of 'internal necking with attached bubble' and 'internal chug with detached bubble' were newly observed. Depending on a nozzle, some regimes expanded, shrank, or moved in the regime map. For the nozzle of 1.55mm, the regime map was similar to Chan and Lee (1982) except that the regime of 'internal chug' was not observed. For the nozzle of 0.115mm, the regime of 'internal chug' appeared even at high pool temperature.

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Three-dimensional flow within a film-cooling hole normally oriented to the main flow (수직분사 막냉각구멍 내부에서의 3차원 유동특성)

  • Lee, Sang-U;Ju, Seong-Guk
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.21 no.9
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    • pp.1185-1197
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    • 1997
  • Three-dimensional flow within a film-cooling hole, which is normally oriented to the main flow, has been measured by using a straight five-hole probe for the blowing ratios of 1.0 and 2.0. The length-to-diameter ratio of the injection hole is fixed to be 1.0 throughout the whole experiments. The result shows that the secondary flow within the hole is strongly affected by the main flow and flow separation at the hole inlet. The higher blowing ratio provides less influence of the main flow on the injectant flow. The three-dimensional flow at the hole exit is considerably altered due to the strong interaction between the injectant and main flow. The aerodynamic loss produced inside the injection hole is mainly attributed to the inlet flow separation.

Numerical Simulation and Supersonic Wind Tunnel Test on the Mixing Process of Transverse Injection to Supersonic Flow (초음속 유동장내에서의 연료의 수직분사 혼합과정에 대한 수치해석 및 초음속 풍동시험)

  • 김성돈;이양지;정인석
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2002.04a
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    • pp.61-61
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    • 2002
  • 스크램 제트 엔진의 설계에서 초음속으로 유입된 공기의 짧은 잔류시간으로 인한 연료-공기의 혼합은 가장 중요하며 해결하기 힘든 문제이다. 전헝적인 비행 조건에서 흡입 공기가 극초음속 비행기 엔진 내에서 잔류하는 시간의 단위는 1 ms 정도이어서 짧은 시간 동안 연료와 공기는 효율적으로 혼합되어야 하며, 최대의 추진력을 얻기 위하여 과도한 공력저항없이 연소 가능한 연료-공기 혼합기를 생성시킬 수 있는 효율적인 연료-공기의 혼합 방법이 요구된다. 현재까지 가장 많이 연구되어 온 혼합 방법은 엔진 입구로 들어오는 공기 유동에 수직 방향으로 연료를 분사하는 것으로 이 방법은 연료 유동 방향과 공기 유동 방향이 수직이기 때문에 추력 손실이 생기는 단점을 갖고 있지만, 초음속으로 유입되는 공기에 수직으로 연료를 분사하게되면 분사 위치 앞에 궁형 충격파가 생겨서 감속되어 유동이 회전하는 재순환영역이 생기고 연료의 혼합이 잘 이루어지는 장점이 있다.

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Study of The Air Jet Normally Injected into Supersonic Stream (초음속 자유유동에 수직으로 분사되는 제트유동장에 관한 연구)

  • 구병수;김희동
    • Journal of the Korean Society of Propulsion Engineers
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    • v.4 no.4
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    • pp.42-49
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    • 2000
  • A computation using the mass-averaged implicit Wavier-Stokes equations has been applied to solve the flow fields of the supersonic jets normally injected into supersonic freestreams and several types of turbulence model has been employed to close the governing equations. The ratio of the freestream to injection flow total pressures has been varied to elucidate the major characteristics of the mixing flow of the two streams. The freestream Mach number has been varied to investigate some change in the injection flow field. The results show that the positions of the separation and reattachment, locating upstream and downstream of the injection hole respectively, are strongly dependent on the ratio of total pressures and the freestream Mach number.

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Turbulent Combustion Dynamics of Transverse Fuel Injection into a Supersonic Crossflow using DES (DES를 이용한 초음속 유동내 수직 연료분사 유동의 난류 연소 해석)

  • Won, Su-Hee;Jeung, In-Seuck;Choi, Jeong-Yeol
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2008.11a
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    • pp.334-337
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    • 2008
  • Three-dimensional unsteady reacting flowfield generated by transverse hydrogen injection into a supersonic mainstream are numerically investigated using DES and finite-rate chemistry model. Comparisons are made with experimental results to investigate the turbulent reacting flow physics. The numerical OH distribution describes well the experimental OH-PLIF result, while the numerical ignition delay time shows some disparity due to the restricted available experimental data.

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