• Title/Summary/Keyword: 수직분사

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Characteristics of the Transverse Fuel Injection into a Supersonic Crossflow using Various Injector Geometries (분사구 형상에 따른 초음속 유동장 내 수직 연료 분사 특성)

  • Kim, Seihwan;Lee, Bok Jik;Jeung, In-Seuck;Lee, Hyoungjin
    • Journal of the Korean Society of Propulsion Engineers
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    • v.22 no.3
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    • pp.53-64
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    • 2018
  • In this study, computational simulation was performed to investigate the characteristics of air/fuel mixing according to the shape of the injector exit when the transverse jet was injected into a supersonic flow. Non-reacting flow simulation was conducted with fixed mass flow rate and the same cross-sectional area. To validate the results, free stream Mach number and jet-to-crossflow memetum ratio are set to 3.38 and 1.4, respectively, which is same as the experimental condition. Further, separation region, structure of the under-expended jet, jet penetration height, and flammable region of hydrogen for five different injectors compared.

Spray Characteristics of Jet According to Position of Injector Hole in Crossflow (횡단유동내 인젝터 홀의 위치에 따른 제트의 분무 특성)

  • Choi, Myeung Hwan;Shin, Dong Soo;Radhakrishnan, Kanmaniraja;Son, Min;Koo, Jaye
    • Journal of the Korean Society of Propulsion Engineers
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    • v.22 no.5
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    • pp.88-96
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    • 2018
  • Effects of injector position and momentum flux ratio on a vertical jet in a cross-flow field are qualitatively studied and displayed using air and water. The position of the injector hole and the momentum flux ratio is changed and image visualization is performed using a shadowgraph technique and a high-speed camera. The visualized images are compared to find differences in spraying using density gradient magnitude image. It is observed that, as the x/d of the apparatus increases, the jet break-up height decreases. When x/d is 0, the spray reaches the bottom and ceiling at any momentum flux ratio.

Unsteady Combustion Phenomena in Scramjet Combustor (스크램제트 연소기의 비정상 연소현상)

  • Choi Jeong-Yeol
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • v.y2005m4
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    • pp.364-367
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    • 2005
  • A series of computational simulations have been carried out for non-reacting and reacting flows in channel-type and divergent scramjet combustor configurations with and without a cavity. Transverse injection of hydrogen is considered with the injection pressure varying from 0.5 to 1.5 MPa. The detailed resolution of the oscillatory flow and flame dynamics are captured at sufficient scale to identify the underlying physical mechanisms, and the role of combustor configuration, cavity and amount of heat addition could be understood.

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Numerical Analysis for Breakup of Liquid Jet in Crossflow (기체 유동에 수직 분사된 액체의 분해에 대한 수치적 해석)

  • Park, Sun-Il;Chang, Keun-Shik;Moon, Yun-Wan;Sah, Jong-Youb
    • Proceedings of the KSME Conference
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    • 2004.11a
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    • pp.1629-1633
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    • 2004
  • Liquid is commonly introduced as transversal jets in venturi scrubber which is one of the gas cleaning equipments. The jet dynamics such as penetration and breakup is of fundamental importance to the dust-collection efficiency. We have developed a model that can numerically simulate the breakup of the liquid jet in crossflow. This simulation consists of models on liquid column, jet surface breakup, column fracture and secondary droplet breakup. These models have been embedded in the KIVA3-V code. We have calculated such parameters as the jet penetration, jet trajectory, droplet size, velocity field and the volume flux distribution. The results are compared with the experimental data in this paper.

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Mixing Augmentation of Transverse Injection of Fuel in SCRamjet Engine (스크램제트엔진 연료수직분사의 혼합특성 개선에 관한 수치연구)

  • Kim, Young-Jin;Lee, Sang-Hyeon
    • Journal of the Korean Society of Combustion
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    • v.4 no.1
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    • pp.117-129
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    • 1999
  • A method for the mixing augmentation of the transverse injection of fuel in a Scramjet combustor is suggested. Based on the fact that the main factor controlling the mixing characteristics in transverse injection is the effective back-pressure (the pressure around the injection hole) it is tried to make a flow expansion near the injection port in order to reduce effective back-pressure. A three dimensional Navier-Stokes code adopting the upwind method of Roe#s flux difference splitting scheme is used. The k-w SST turbulence model turbulence model is used to calculate the turbulent viscosity. It is shown that the reducing of the effective back-pressure make it possible to increase the penetration distance and to increase the mixing rate without excessive losses of stagnation pressure. Also, it is shown that the streamwise vorticity generated by baroclinic torque has great influences on the mixing process.

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Unsteady Numerical Analysis of Transverse Injection Jet into Supersonic Mainstream (초음속 주유동에 수직 분사되는 제트의 비정상 수치해석)

  • Choi Jeong-Yeol;Yang Vigor
    • 한국전산유체공학회:학술대회논문집
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    • 2003.08a
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    • pp.126-131
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    • 2003
  • A series of computational simulations have been carried out for supersonic flows in a scram jet engine with and without a cavity. Transverse injection of hydrogen, a simplest form of fuel supply, is considered in the present study with the injection pressure varying from 0.5 to 1.5 MPa. The corresponding equivalence ratios are 0.167 - 0.50. The work features detailed resolution of the flow dynamics in the combustor, which was not typically available in most of the Previous studies. In particular, oscillatory flow characteristics are captured at a scale sufficient to identify the underlying physical mechanisms. Much of the flow unsteadiness is related not only to the cavity, but also to the intrinsic unsteadiness in the flowfield. The interactions between shock waves and shear layer may cause a large excursion of flow oscillation. The role of the cavity and injection pressure are examined systematically.

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Spray Characteristics of Superheated Swirl Spray Vertically Introduced into Convective Cross-flow (대류유동으로 수직 분사된 과열 와류분무의 분무특성)

  • Lee, Hae-Cheon;Yoon, Woong-Sup
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2010.11a
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    • pp.395-398
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    • 2010
  • 감압비등에 의한 미립화는 더 미세한 직경의 액적을 얻을 수 있고, 분무각이 증가하며, 더 좋은 혼합특성을 갖는 다는 점에서 단순 압력식 미립화와 차이가 난다. 감압비등이란 과열된 액체를 포화 압력 이하의 대기 중으로 분사하여 급격한 비등에 의해 이루어지는 미립화이다. 본 연구는 금속 연료를 이용한 추진기관의 산화제인 물 공급기술에 감압비등과정을 이용한 와류분무를 적용시키기 위해 수행됐다. 분열길이와 같은 거시적 특성은 Charge-Couple Device(CCD) 카메라를 이용해 측정하였고, Sauter Mean Diameter(SMD)와 SMD분포와 같은 미시적 특성은 Global Sizing Velocimetry(GSV) 시스템을 이용해 측정했다. 실험은 압력과 온도, 대류 속도를 변화시키며 진행했다.

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Characteristics of the Spray and Combustion in the Liquid Jet (수직 분사되는 연료제트의 분무 및 연소특성)

  • 윤현진;문수연;손창현;이충원
    • Journal of the Korea Institute of Military Science and Technology
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    • v.5 no.1
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    • pp.107-115
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    • 2002
  • In this paper, spray and combustion characteristics of a liquid-fueled ramjet engine were experimentally investigated. The spray penetrations were measured to clarify the spray characteristics of a liquid jet injected transversely into the subsonic vitiated airstream, which Is maintained a high velocity and temperature. The spray penetrations are increased with decreasing airstream velocity, increasing airstream temperature, and increasing air-fuel momentum ratio. To compensate our results of penetrations, the new experimental equation were modified from Inamura's equation. In the case of insufficient penetration, the combustion phenomenon in ram-combustor were unstable. Therefore, the sufficient penetration must be considered to make a stable flame.

An Investigation on the Spray Characteristics of Steady/Plused Jet in Crossflow in Model Ramjet Combustor (모델 램제트 연소기 내에서의 정상/가진 수직 분무 특성 연구)

  • Kim, Jin-Ki;Song, Jin-Kwan;Kim, Min-Ki;Yoon, Young-Bin;Hwang, Yong-Seok
    • Journal of ILASS-Korea
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    • v.13 no.2
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    • pp.99-106
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    • 2008
  • In this study, spray characteristics research of steady/pulsed injection in crossflow was performed experimentally in the model ramjet combustor. High-speed-camera photography was performed through a visualization window of model combustor, and then, steady and pulsed spray structures were observed and analyzed. Varying influx air temperature and fuel species, we could obtain the trajectory correlation in the steady injection case. In the experiment of pulsed injection, it is found that the pulsed frequency hardly influences spray trajectory. Also, it is found that, in the same injection pressure differential, the trajectory correlation of steady condition can be used for estimating pulsed spray trajectory.

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The Heat Transfer Characteristics on Impinging Surface by Oblique Jet (경사 제트에 의한 충돌면에서의 열전달 특성)

  • 이창호;조형희;정학재
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 1998.10a
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    • pp.28-28
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    • 1998
  • 단일 충돌제트의 경우 충돌면에서의 열전달 효과는 제트 출구와 충돌면 사이의 간격, 노즐 형상에 따른 제트출구의 초기조건, Re$_{D}$수 변화와 충돌면의 형상이나 표면거칠기 등에 따라 변화하게 된다. 그러나 수직 충돌제트의 경우 정체영역에서의 국소적인 열전달 향상은 용이하나 반경 방향으로 열전달이 점차 감소하게 된다. 따라서 충돌면의 전반적인 열전달 향상을 위해서는 열전달이 정체점보다 상대적으로 낮은 영역에서 열전달 향상이 필요하다. 또한, 실제 적용시 충돌면의 형상이나 협소한 공간에서 노즐위치의 제약으로 인하여 충돌제트가 수직으로 분사되는 경우보다 경사진 제트가 더욱 많이 응용된다. 더욱이, 수직충돌제트가 사용되는 많은 상황에서도 주위의 다른 공기 흐름의 영향으로 인하여 실제 제트가 경사각을 갖고 분사되어진다 이러한 경사충돌제트의 중요성에도 불구하고 경사충돌제트에 대한 연구는 수직충돌제트에 대한 연구보다 상대적으로 적게 이루어져 왔다.

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