• Title/Summary/Keyword: 막냉각방법

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Capability of Turbulence Modeling Schemes on Estimating the Film Cooling at Parallel Wall Jet-Nozzle Configuration (평행 벽 제트-노즐 형상에서 난류모델별 막냉각 예측 능력)

  • Lee, Jun;Kim, Yoo
    • Journal of the Korean Society of Propulsion Engineers
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    • v.13 no.1
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    • pp.10-18
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    • 2009
  • Numerical simulation has been performed in this study to investigate the capabilities of turbulence modeling schemes on estimating the film cooling at a referenced parallel wall jet-nozzle configuration. Also a additional simulation has been performed for film cooling under 2-dimensional axis symmetry conditions at a parallel wall jet-nozzle configuration. It was concluded that the best turbulence model is the standard $k-{\epsilon}$ model with enhanced wall functions. Also a additional simulation showed the film cooling characteristics that are resonable physically.

Film Cooling by a Row of Jets in a Gas Turbine Blade (가스터빈블레이드에서 일렬의 제트에 의한 막냉각특성 연구)

  • 이용덕;이재헌
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.18 no.7
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    • pp.1851-1865
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    • 1994
  • The objective of the present study is to predict the film cooling effectiveness by a row of holes at various injection ratios and injection angles. Numerical calculations have been performed to investigate the characteristics of flow and temperature distributions in a region near the down-stream of injection hole including the region of adverse pressure gradient. The elliptic turbulent 3-dimensional governing equations with variable thermal properties using the low-Reynolds number k-$\bar{varepsilon}$ model was solved by SIMPLE algorithm. The results showed that the presence of adverse pressure gradient and secondary vortex in the region near the downstream of injection hole induces large temperature gradent. The $45^{\circ}$ injection has higher averaged film cooling effectiveness than $60^{\circ}$ injection. But neverthless the $90^{\circ}$ injection has greater deviation from a flat plate than $45^{\circ}$ and $60^{\circ}$ injection, the $90^{\circ}$ injection has higher averaged film cooling effectiveness than $45^{\circ}$ and $60^{\circ}$ injection in the region near the downstream of injection hole.

A Study on Film Cooling Characteristics of Liner in Liquid Rocket Engine (액체로켓엔진에서의 상온 기체를 이용한 라이너 막냉각 특성 연구)

  • Jeon, Jun-Su;Lee, Yang-Suk;Lee, Dong-Hyeong;Kim, Yoo;Ko, Young-Sung;Chung, Hae-Seung
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2007.11a
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    • pp.170-173
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    • 2007
  • Cooling characteristics of a liner were investigated by a film cooling method using a gas nitrogen in a rocket engine. High temperature gas of this test was made by mixing liquid nitrogen with combustion gas of a liquid rocket. A supply system of gas nitrogen was additionally constructed to the existing test facility of liquid rocket engine, and a new test section consisted of a liner and a gas injection ring was manufactured. A 10 second firing test for finding cooling characteristics of the liner was successfully conducted and liner surface temperatures and hot gas temperature was obtained.

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3-Dimensional Analysis for Film Cooling adjacent Injection Hole (분사구 인접영역에서의 막냉각에 관한 3차원 해석)

  • 이용덕;이재헌
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.17 no.10
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    • pp.2590-2600
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    • 1993
  • The present paper describes numerical predictions for the film cooling effectiveness from a row of hole at various injection ratios and injection alngles.Numerical calculations were performed to investigate film cooling effectiveness and the characteristics of flow and temperature distributions in the region near the downstream of injection hole including the region of adverse pressure gradient. The elliptic 3-dimensional governing equations with variable thermal properties were solved by SIMPLE algorithm. The results showed that the presence of adverse pressure gradient in the region near the downstream of injection hole induces large temperature gradient. At injection angle of $35^{\circ}$ the average film cooling effectiveness was increased as increased of injection ratio up to 1.0. At injection angle of $90^{\circ}$ however, the average film cooling effectiveness was decreased from injection ratio larger than 0.4.

CFD를 이용한 막냉각(Film-Cooling) 해석

  • Na, Sang-Gwon
    • The KSFM Journal of Fluid Machinery
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    • v.11 no.6
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    • pp.64-68
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    • 2008
  • 막 냉각 연구를 위해 CFD를 이용할 때 적용 한계 및 그 타당성을 검증하고자 하였다. 이 글에서는 냉각공기공으로부터 분출된 냉각공기가 고온 고속으로 흐르는 주유동과 평판 사이에 벽면을 고온의 가스에 노출되는 것을 막기 위해 위치시킨 막냉각공기 흐름의 형태를 CFD를 이용하여 분석하였다. 모든 경계조건 및 격자계 그리고 검증 단계의 예까지 서술함으로써 이러한 CFD를 이용할 때 유용하게 적용될 방법들을 제공하였다.

A Study on the Cooling Mechanism in Liquid Rocket Engine of 10tf-thrust Level using Kerosene as a Fuel (케로신을 연료로 하는 10톤급 액체로켓엔진의 냉각 기구에 관한 연구)

  • 한풍규;조원국;조용호
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2003.10a
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    • pp.83-88
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    • 2003
  • An analytical study was carried out to evaluate the regenerative cooling characteristics in the liquid rocket engine of a 10tf-thrust level using kerosene as a fuel. As a supplementary cooling method, a radiative cooling was applied to the nozzle extension. It was found out from this work that the cooling system with the regenerative and radiation cooling only is not adaptable as a cooling method for the liquid rocket engine of a 10tf-thrust level using kerosene as a fuel for the 2nd stage of the space launch vehicle. So, additional cooling method, curtain cooling was introduced and analyzed. Curtain cooling was very effective to reduce the thermal and thermo-structural instability.

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A Numerical Study on Cooling Characteristics of a Rocket-engine-based Incinerator Devised for High Burning Rate of Solid Particles (고체입자의 높은 연소율을 갖기 위해 고안된 로켓 엔진 기반 소각로의 냉각 해석)

  • Son, Jinwoo;Sohn, Chae Hoon
    • Journal of the Korean Society of Propulsion Engineers
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    • v.20 no.2
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    • pp.1-10
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    • 2016
  • Cooling characteristics are investigated numerically in the chamber for high-performance burnout of wastes with solid phase. Before the combustion chamber is manufactured, combustion analysis is performed for evaluation of burning rate and cooling performance. A water cooling method is applied and its feasibility for cooling is examined depending on coolant flow rate. Another method of complex cooling is adopted by combining air film cooling with water cooling, leading to improved cooling performance.

Effect of Free Stream Turbulence Intensity on Heat/Mass Transfer Characteristics Around a Film Cooling Hole (주유동의 난류강도가 막냉각홀 주위의 열/물질전달 특성에 미치는 영향)

  • 이동호;김병기;조형희
    • Journal of the Korean Society of Propulsion Engineers
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    • v.2 no.2
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    • pp.56-63
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    • 1998
  • The present study investigated local heat transfer characteristics around a film cooling hole with variations of free stream turbulence intensity The film cooling jet is injected through a single hole inclined at $30^{\cire}$ to the surface and laterally at $45^{\cire}$ for the blowing rates of 0.5, 1.0 and 2.0. Turbulence generating grids are used at upstream of the film cooling hole to change the turbulence intensity of free stream. Free stream turbulence intensity without grids is 0.5%. Two different turbulence generating grid is installed at different at locations upstream of the film cooling hole so that turbulence intensity of free stream varies from 3% to 10%. The naphthalene sublimation technique has been employed to determine local heat/ mass transfer coefficients. With low free stream turbulence intensity, heat/mass transfer augmented area by coolant or free stream is distinguished evidently. However, when free stream turbulence intensity is high, heat transfer is enhanced in all region and heat transfer enhanced regions are not clearly divided due to vigorous mixing of coolant and free stream. The peak values of heat/mass coefficients are decreased and the distributions of heat/mass transfer coefficients are more uniform with high turbulence intensity. The effect of turbulence intensity on heat transfer characteristics is more evident as blowing rate is higher.

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막냉각 및 재생냉각 난류유동

  • Park, Tae-Seon
    • Journal of the KSME
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    • v.56 no.9
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    • pp.49-53
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    • 2016
  • 액체로켓엔진은 연소실의 온도가 약 3,600K로서 냉각시스템은 필수적이다. 지금까지 대표적으로 사용되어온 냉각방법은 재생냉각과 막냉각으로 아임계압력에서 다양한 실험연구에 의해서 설계가 진행되어 왔다. 아임계압력에서 얻어진 유동구조 이해 및 설계경험식은 초임계 압력에서는 물성치가 급격히 변하기 때문에 재정립될 필요가 있다. 특히 열전달 성능을 좌우하는 난류유동구조가 크게 바뀌기 때문에 초임계 유체에 대한 난류유동 및 열전달연구가 진행될 필요가 있다. 이 글에서는 초임계 압력조건에서 난류열전달 연구동향을 소개하고자 한다.

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Improvement of Cooling Effects of Pylon Injector for Scramjet Combustor (스크램제트 연소기용 파일런 분사기 냉각성능 개선 연구)

  • Lee, Sang-Hyeon
    • Journal of the Korean Society of Propulsion Engineers
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    • v.15 no.5
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    • pp.10-18
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    • 2011
  • A new film cooling method to protect the pylon injector from aerodynamic heating for a scramjet combustor is proposed and verified with numerical methods. The conditions for the Mach 8 flight at an altitude of 35km are considered. Air is considered as a coolant. Three-dimensional Navier-Stokes equations with $k-{\omega}$ SST turbulence model are used. A downward injection of coolant from the top of the pylon gives higher cooling effects with less mass flow rate of coolant than the upward coolant injection from bottom of the pylon. Also, the downward injection shows little flow separation due to the favorable pressure gradient and does not disturb the flowfields near pylon injector, which results in reduction of pressure losses.