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Mach 4 Scramjet Testing in a Shock Tunnel
Gisu Park(박기수),Jongryul Byun(변종렬),Hojin Choi(최호진),Youin Jin(진유인),Kiyoung Hwang(황기영) 한국추진공학회 2013 한국추진공학회 학술대회논문집 Vol.2013 No.5
The shock tunnel is known to be uniquely capable of simulating flow-field environments that can replicate supersonic/hypersonic flight conditions. As a consequence of the strong interest in hypersonic aerospace planes and research in Republic of Korea, attention has been given on this type of facility and the intermediate-sized shock tunnel has lately been built at KAIST. This paper discusses the performance of our tunnel and some of the recent progress made on the Mach 4 scramjet testing.
High Speed Propulsion System Test Research Using a Shock Tunnel
Gisu Park(박기수),Jongryul Byun(변종렬),Hojin Choi(최호진),Yuin Jin(진유인),Chul Park(박철),Kiyoung Hwang(황기영) 한국추진공학회 2014 한국추진공학회지 Vol.18 No.5
Shock tunnels are known to be capable of simulating flow-field environments of supersonic and hypersonic flights. They have been operated successfully world-wide for almost half a century. As a consequence of the strong interest in hypersonic vehicles in Korea, attention has been given on this type of facility and so an intermediate-sized shock tunnel has lately been built at KAIST. In the light of this, this paper presents our tunnel performance and some of the model scramjet test data. The freestream flow used in this work replicates a supersonic combustor environment for a Mach 5.7 flight speed.
Characteristic Study of Ethylene Autoignition in High Enthalpy Flows
Gisu Park(박기수),Hojin Choi(최호진),Jongryul Byun(변종렬),Yuin Jin(진유인),Kiyoung Hwang(황기영) 한국추진공학회 2013 한국추진공학회 학술대회논문집 Vol.2013 No.12
Ignition and flame-holding characteristics of ethylene transverse jets in high enthalpy supersonic crossflows have been experimentally investigated in this work. This work contributes to the growing database on supersonic combustion flows by providing information to help fill the voids regarding an overall understanding of cavities for use as scramjet flame-holders. The experiments were conducted in a shock tunnel using a scramjet model. An optical visualization as well as chemiluminescence techniques were employed to investigate the autoignited flame-holding characteristics. Various flow conditions having a broad range of temperatures at a fixed level of fuel concentration were considered.
최호진(Hojin Choi),현형수(Hyungsoo Hyun),변종렬(Jongryul Byun),박의용(Euiyong Park),윤현걸(Hyungull Yoon),임진식(Jinshik Lim) 한국추진공학회 2011 한국추진공학회 학술대회논문집 Vol.2011 No.5
덕티드로켓 추진기관에 사용되는 불완전연소 가스발생기를 설계/제작하고 연소시험을 수행하여 그 연소특성을 분석하였다. 추진시스템 설계요구조건을 바탕으로 가스발생기를 설계하고 산화제 함유량을 줄이고 금속연료 함량을 증가시킨 불완전연소용 고체연료 조성을 개발하여 가스발생기를 제작하였고, 이를 이용한 연소시험을 통해 다상 유동의 불완전연소 가스가 존재하는 가스발생기의 성능예측을 위해서는 별도의 해석기법이 요구됨을 확인하였다. The combustion characteristics of fuel-rich gas generator which could be adopted to Ducted Rocket propulsion system is investigated. The gas generator is designed considering the design requirements of propulsion system then solid fuel, which is developed by reducing the contents of oxidizer and increasing the contents of metallic solid particle, is loaded in the manufactured gas generator. The results of combustion test shows the necessity of the special analysis tool for estimating the gas generator performance where multi-phase flow of fuel-rich gas exists.
Characteristic Study of Fuel Injection into a Supersonic Flow in a Shock Tunnel
Gisu Park(박기수),Hojin Choi(최호진),Jongryul Byun(변종렬),Youin Jin(진유인),Kiyoung Hwang(황기영) 한국추진공학회 2013 한국추진공학회 학술대회논문집 Vol.2013 No.5
Flow features of helium and ethylene transverse jets exposed in a supersonic flow have been examined experimentally. Flow visualization images were obtained in a shock tunnel using a Schlieren technique. Both the helium and the ethylene experimental data showed that jets weekly penetrate deep into the crossflow just downstream of the injection port when the velocity shear is strong at high Reynolds number. At sufficient distance downstream from the injection port, however, the jets seem to recovered their momentum and the deviations from the existing data were found to be small.
박기수(Gisu Park),진유인(Yuin Jin),최호진(Hojin Choi),변종렬(Jongryul Byun),황기영(Kiyoung Hwang) 한국추진공학회 2013 한국추진공학회 학술대회논문집 Vol.2013 No.12
스크램제트 연소기 내부에서의 초음속 유동, 혼합 및 연소현상에 대한 이해증진을 목적으로 고엔탈피 초음속 유동에 대하여 수직방향으로 분사되는 에틸렌 제트의 유동 특성을 실험적으로 연구하였다. 실제 비행조건과 유사한 고엔탈피 조건을 모사하기 위하여 충격파 터널을 사용하였으며, 카울과 단공 연료분사 노즐을 가진 스크램제트 모델 연소기를 구현하였다. 이러한 연소기 내부의 유동장을 관찰하기 위해 고속 쉐도우그래프 기법을 적용하여 가시화 하였다. 계측된 영상의 후 처리를 통해 에틸렌 제트의 침투거리 및 충격파 구조를 분석하였고 공동의 유무에 따른 영향을 살펴보았다. Flow field characteristics of ethylene transverse jets in high enthalpy supersonic crossflows have been experimentally investigated to provide overall understanding of supersonic flow, mixing and combustion in scramjet combustor. The experiments were conducted in a shock tunnel to simulate the real flight condition using scramjet model combustor containing cowl and single fuel injection nozzle. As an optical visualization method, a shadowgraph technique was employed to capture flow-fields inside a combustor. By image processing the captured images, jet penetrating behaviors as well as shock structures were analyzed including the effect of cavity in combustor.
안중기(Joongki Ahn),이창혁(Changhyuk Lee),최진(Jin Choi),변종렬(Jongryul Byun) 한국추진공학회 2015 한국추진공학회 학술대회논문집 Vol.2015 No.5
이 논문은 이중모드 램제트의 천이특성 모델링 기법을 연구한 내용을 담고 있다. 준 1차원 방정식을 이용하여 램모드에서 스크램모드로 천이특성을 시뮬레이션 하였다. 천이특성 모델링에서 어려운 점은 thermal throat부근에서 해를 구하는 부분이다. 이곳에서는 흐름의 질식이 발생하여 흐름속도가 마하 1이 됨에 따라 방정식의 해는 특이상태가 된다. 본 연구에서는 해석적인 방법을 이용하여 마하 1영역에서의 해를 계산하였다. 계산결과, 안정적인 수렴성과 기존 연구결과에 비해 물리적으로 타당한 결과를 확인할 수 있었다. This paper presents the modelling technique of the transition of DMR(Dual Model Ramjet). The transition from ram to scram mode combustion for DMR is studied by a quasi 1-dimensional model. One of the challenges for the simulation of transition is to calculate the properties at the thermal throat. As the flow is choked and becomes Mach 1 at the thermal throat, the solution of equations becomes singular. In this paper, the solution at the sonic point is calculated by analytic way. The results show good convergence and reasonable characteristics at the sonic point.
초음속 공기흡입식 엔진 연소기의 연소불안정 발생 및 분석
황용석(Yongseok Hwang),이종근(Jongguen Lee),최호진(Hojin Choi),길현용(Hyunyong Gil),변종렬(Jongryul Byun),윤현걸(Hyungull Yoon),임진식(Jinshik Lim) 한국추진공학회 2009 한국추진공학회 학술대회논문집 Vol.2009 No.5
램제트 엔진은 다른 공기흡입식 엔진에 비해 상대적으로 매우 긴 유로를 지니고 있음으로 인해 저주파 연소불안정에 취약한 단점을 지니고 있다. 본 연구에서는 램제트 엔진에서 발생하는 연소 현상과 동일한 메카니즘을 모사할 수 있는 연료분사장치 및 V-gutter 형태의 화염안정화장치를 장착한 소형 연소기를 설계/제작하여, 램제트 연소기에서 발생할 수 있는 연소불안정 현상을 시현하였다. 이 연소기에서 발생한 연소불안정은 연소시스템의 음향학적인 공진 주파수와 유사하게 나타남을 확인하였으며, 이를 통해 thermo-acoustic coupling에 의한 전형적인 연소 불안정이 발생하였음을 확인할 수 있었다. Ramjet engine is weak for low frequency combustion instability because of their long air flow passasge. A model combustor which has fuel injector and V-gutter shaped flame holder was designed and fabricated in order to simulate a combustion mechanism of ramjet engine, and it could demonstrate combustion instability which might occur in ramjet combustor. The frequency of the instability was very similar to that of acoustic resonance frequency of combustor, and it proved that a typical combustion instability by thermo-acoustic coupling occurred.