• Title/Summary/Keyword: 제트후류

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Investigation of Exhaust Facility of Liquid Rocket Propulsion System (액체로켓 추진기관의 후류처리장치 고찰)

  • Cho, Nam-Kyung;Lee, Kwang-Jin;Han, Young-Min
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2012.05a
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    • pp.133-138
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    • 2012
  • Exhaust facility has basically the role of flame deflector, and considering additional functions, it can be classified by noise/emission suppressor and altitude simulation facility. In this paper, principles of flame deflector, jet pump, emission suppression are presented for exhaust treatment facility. Principles of noise suppression caused by Mach wave mitigation, jet energy mitigation by water evaporation and condensation are shown. In addition, a concept of vertical exhaust treatment facility is presented applying basic principles aforementioned.

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Acoustic Analysis of Exhaust Supersonic Jet From a Rocket Motor Using 2-D Axis-symmetric Computational Analysis (2차원 축대칭 전산해석을 이용한 초음속 로켓 제트 음향 해석)

  • Yang, Young-Rok;Jeon, Hyuck-Soo
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.48 no.9
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    • pp.725-730
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    • 2020
  • This study was conducted to reduce the computation time required for the computational acoustic analysis of the supersonic rocket jet plume. In order to reduce the computation time, computational acoustic analysis was performed assuming that the supersonic jet plume is a two-dimensional axis-symmetric problem. The results of computational acoustic analysis showed similar results to the acoustic load measurement results. Through this study, it was confirmed that the acoustic load prediction of the supersonic rocket jet plume can be predicted using a two-dimensional axis-symmetric computational analysis.

Research of stability about aerodynamic levitation using jet (제트를 이용한 구체 부양 안정성 연구)

  • Han, Song-Lee;Yun, Tae-Gyun;Gu, Jun-Mo
    • Proceeding of EDISON Challenge
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    • 2013.04a
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    • pp.305-309
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    • 2013
  • 본 연구에서는 유체역학적인 후류 효과를 제어하고 항력을 이용하여 구체를 안정적으로 부양하는 방법을 해석 및 실험적으로 고찰하였다. 물체를 공중에 부양할 때는 물체가 받는 중력과 제트에 의하여 공급되는 항력이 평형을 이루어야 한다. 이 때 공기의 흐름의 레이놀즈 수에 따라 공기가 구체를 지나가며 구체후면에 생기는 후류에 의하여 부양상태가 불안정하게 될 수 있다. 구체의 운동이 제트에 의하여 안정되는 현상은 베르누이 및 코안다 효과로 설명할 수 있다. 에디슨을 이용하여 레이놀즈 수에 따른 실린더에 작용하는 항력과 후류에 의한 불안정화 힘을 해석적으로 구하였으며 이를 실험적으로 고속카메라를 이용하여 부양 거리, 안정도 등을 측정하여 비교하였다. 고찰 결과 레이놀즈 수가 작을수록 더 안정됨을 확인하였다.

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The Whole Region Pressure Measurement of Cavity Downstream using PSP Technique (PSP를 이용 다양한 공동 후류의 전역적 압력분포 측정)

  • Seo, Hyung-Seok;Oh, Ju-Young;Jeon, Young-Jin;Lee, Jae-Woo;Byun, Yung-Hwan
    • Journal of the Korean Society of Propulsion Engineers
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    • v.11 no.6
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    • pp.50-57
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    • 2007
  • Pressure Sensitive Paint(PSP) means a reacting paint in pressure. PSP can measure continuous pressure field by analyzing the oxygen quantity using optical method. The surface pressure of down stream after the sonic jet that injected transversely into the supersonic freestream was measured by PSP technique. Moreover the effect of various rectangular shaped cavities in front of the jet was measured by PSP technique. A comparison of the PSP results with conventional pressure tap and CFD indicates good agreement. Until now, the results of numerical analysis were compared with the discrete points such as the results of pressure tap. In this study, the whole region pressure was measured using PSP technique and its results were similar to CFD. Therefore, the flow phenonenon of cavity downstream was clearly grasped.

Effects of Pulsating Jet Blowing on Stall Control of Two Dimensional Elliptic Airfoil (이차원 타원형 날개꼴의 실속제어에서 간헐제트 브로잉의 효과)

  • Lee, Ki-Young;Sohn, Myong-Hwan;Jeong, Hung-Seok
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.33 no.9
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    • pp.1-8
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    • 2005
  • This paper explored the effects of separation control through the use of pulsating jet blowing on a two dimensional elliptical airfoil. To develop an active control technique of flow separation, a flow control actuator utilizing continuous/pulsed jet of pressurized air was designed and installed in a wind tunnel testing model of elliptic wing. PIV measurement and flow visualization of the wing near field were conducted to access the feasibility and effectiveness of the pulsed jet blowing on controlling the stall of the elliptical wing in subsonic flow. PIV experimental results show that separation control can provide significant reduction in turbulent flow wake and separation bubbles by jet blowing. The pulsating jet blowing is more effective on the separation control than continuous one. Increased jet frequency suppressed the turbulent separated flow wake effectively at even higher AOAs.

Effect of a Turbulent Wake on Two-Dimensional Subsonic Jet (노즐내 물체의 후류가 아음속 이차원 제트구조에 미치는 영향에 관한 연구)

  • Kim, Tae-Ho;Lee, Sang-Chan;Yoon, Bok-Hyun;Oh, Dae-Geun;Kim, Heuy-Dong
    • Proceedings of the KSME Conference
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    • 2003.11a
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    • pp.986-991
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    • 2003
  • A turbulent wake generated by a cylinder in nozzle contraction affects to the jet flow characteristics. In this study, a computational work to investigate the effect of the turbulent wake on two-dimensional subsonic jet was carried out with three different kinds of nozzle. Computations are applied to the two-dimensional unsteady, Navier-Stokes equations. Several kinds of turbulent models and wall functions are employed to validate the computational predictions. It was known that the wake flow enhanced the spread of the jet flow, compared with no wake flow condition. It was also found that the jet core is shortened by the wake flow developed from a control cylinder.

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An Experimental Investigation on the Flow Field around the Wing Having a Circular Damage Hole (원형 손상 구멍이 있는 날개 주위 유동장에 관한 실험적 연구)

  • Lee, Ki-Young
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.36 no.10
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    • pp.954-961
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    • 2008
  • An experimental study has been conducted to investigate the flow field around the wing having a circular damage hole. The damage was represented by a circular hole passing through the model with 10% airfoil chord diameter and normal to the chord. The hole was centered at quarter or half chord. The PIV flow fields and static pressure measurements on the wing upper and lower surface were carried out at Rec=2.85×105 based on the chord length. The PIV results showed the two types of flow structures around a damage hole were formed. The first one was a weak jet that formed an attached wake behind the damage hole. The second one resulted from increased incidence; this was a strong jet where the flow through the hole penetrates into the free-stream resulting in extensive separation of oncoming boundary layer flow and development of a separated wake with reverse flow. The surface pressure data showed a big pressure alteration near the circular damage hole. The severity of pressure alteration was increased as a damage hole located nearer to the leading edge.

Numerical Study of Unsteady Supersonic Flow Behind a Rearward-Facing Step with Slot Injection (측면제트분사가 있는 후향계단 후류의 비정상초음속유동에 대한 수치적 연구)

  • Kim,Jong-Rok;Kim,Jae-Su
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.31 no.1
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    • pp.97-103
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    • 2003
  • Numerical research has been done for the transverse jet behind a rearward-facings step in turbulent supersonic flow without chemical reaction. Purpose of transverse jet is to enhance mixing of the fuel in the combustor. Two-dimensional unsteady flowfields generated by slot injection into supersonic flow are numerically simulated with the Navier-Stokes equations with two-equation k-$\varepsilon$ turbulence model. Numerical method is used high-order upwind TVD scheme. Eight cases are computed for different slot momentum flux ratios and slot position at downstream of the step. The flow is very similar to the cavity flow, because the jet acts as an obstacle. The numerical results thus show the periodic phenomenon.

Effect on the Wake Flow according to Various length of Rectangular Cylinder in a Parallel Arrangement (병렬구조를 가진 장방형 실린더의 길이가 후류 유동에 미치는 영향)

  • Choe, Sang-Bom;Cho, Dae-Hwan
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.20 no.6
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    • pp.760-767
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    • 2014
  • An experimental study is carried out to investigate the effect of jet stream in the gab of rectangular cylinders with different length in a parallel arrangement by using PIV method in a circulating water channel. The height(h) of the rectangular cylinder and the gap between the cylinder is 10mm, and the width(B) which is 300mm. The length of the model for flow direction was applied to 30mm, 60mm, 90mm & 120mm, The aspect ratio of a model on the basis of height(H=30mm) is 1, 2, 3 and 4. Reynolds number $Re=1.4{\times}10^4$, $Re=2.0{\times}10^4$, $Re=2.9{\times}10^4$ based on the height(H) of model for the distance of tidal distributions as of water depth have been applied during the whole experiments. The measurement area was set to 5H rear of the cylinder. As a result, Vortex size in the wake area were increased as velocity increased. and high aspect ratio increased through-flow velocity component in the near wake. Velocity deficit increased highly after near-wake area and low aspect ratio.

A Study on Effects of Baffle on Impinging Water Jet with wall jet inlet flow (벽면제트류가 유입되는 충돌수분류유동에 배플이 미치는 효과에 관한 연구)

  • Choi, Jung-Sik;Oh, Woo-Jun;Cho, Dae-Hwan
    • Proceedings of KOSOMES biannual meeting
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    • 2009.06a
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    • pp.87-88
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    • 2009
  • In evaporating distillation plant velocity characteristic of fluid to flow in a evaporator have great influence on flash phenomenon. In This experimental study about impinging water jet region having the inflow of wall jet flow and effect of baffle height to flow velocity in after baffle region, making a application by PIV.

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