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김문기(Munki Kim),한영민(Yeoung-Min Han),김종규(Jonggyu Kim),안규복(Kyubok Ahn),이광진(Kwang-Jin Lee),최환석(Hwan-Seok Choi) 한국추진공학회 2009 한국추진공학회 학술대회논문집 Vol.2009 No.11
한국형 발사체용 액체로켓엔진을 개발하기 위한 75톤급 연소기 기술검증 시제를 제작하여 수류시험 및 점화시험을 수행하였다. 기존의 연소기에 새롭게 도입된 기술인 점화, 막냉각, 산화제 선공급방식을 반영하기 위해 시험설비를 수정 및 개량하였다. 산화제 및 연료 수류시험을 통해 공급라인, 점화기 라인, 연소기의 수력학적 특성, 추진제 충전시간을 파악하여 점화순서를 결정하였다. 점화 cyclogram을 통해 점화기의 점화시험을 성공적으로 수행하였으며, 향후 연소시험을 위한 기초 자료를 습득하였다. Cold flow and ignition tests were performed for a technology demonstration model of a 75-tonf thrust chamber which is a candidate liquid rocket engine for a next Korea Space Launch Vehicle. The test facility was modified to support the new concepts of the thrust chamber such as ignition system, film cooling and LOx leading supply. The hydrodynamic characteristics of the supply pipelines, thrust chamber and igniter as well as the filling time of the propellants were obtained through the cold flow tests on the LOx and kerosene and the ignition cyclogram was determined using the results. The ignition test was successfully accomplished according to the cyclogram and therefore, a basic information was obtained for further hot firing tests.
김문기(Munki Kim),오정석(Jeong-suk Oh),최영일(Young-il Choi),윤영빈(Youngbin Yoon) 한국연소학회 2006 KOSCOSYMPOSIUM논문집 Vol.- No.-
This paper investigates the effects of acoustic forcing on NOx emissions and mixing process in the near field region of turbulent hydrogen nonpremixed flames. The resonance frequency was selected to force the coaxial air jet acoustically, because the resonance frequency is effective to amplify the forcing amplitude and reduce NOx emissions. When the resonance frequency is acoustically excited, a streamwise vortex is formed in the mixing layer between the coaxial air jet and coflowing air. As the vortex develops downstream, it entrains both ambient air and combustion products into the coaxial air jet to mix well. In addition, the strong vortex pulls the flame surface toward the coaxial air jet, causing intense chemical reaction. Acoustic excitation also causes velocity fluctuations of coaxial air jet as well as fuel jet but, the maximum value of centerline fuel velocity fluctuation occurs at the different phases of Ф=180° for nonreacting case and Ф=0° for reacting case. Since acoustic excitation enhances the mixing rate of fuel and air, the line of the stoichiometric mixture fraction becomes narrow. Finally, acoustic forcing at the resonance frequency reduces the normalized flame length by 15 % and EINOx by 25 %, compared to the flame without acoustic excitation.
김문기(Munki Kim),임병직(Byoungjik Lim),김종규(Jong-Gyu Kim),최환석(Hwan-Seok Choi) 한국추진공학회 2013 한국추진공학회 학술대회논문집 Vol.2013 No.12
7톤급 가스발생기 개발시제 3기를 제작하여 설계점 및 탈설계점 조건에 대해 연소시험을 성공적으로 수행하였다. 연소시험을 통해 분사기 차압, 연소가스 온도 등의 연소 성능과 연소 안정성을 확인하였다. Three development test articles of the gas generator for 7 tonf-class liquid rocket engine were manufactured and the hot-firing tests were successfully performed on the design and off-design conditions. From the test results, the combustion performance on the pressure difference of injectors and the temperature variation of burnt gas was investigated. The combustion instability was also checked.
김문기(Munki Kim),서성현(Seonghyeon Seo),안규복(Kyubok Ahn),임병직(Byoungjik Lim),김종규(Jong-Gyu Kim),이광진(Kwang-Jin Lee),한영민(Yeoung-Min Han),최환석(Hwan-Seok Choi) 한국추진공학회 2010 한국추진공학회 학술대회논문집 Vol.2010 No.5
75톤급 가스발생기 기술검증시제에서 나타난 산화제 분사기 차압의 증가 원인을 파악하기 위하여 축소형 가스발생기를 설계, 제작하였다. 설계점 및 탈설계점 시험 조건을 포함한 총 6회의 연소시험을 성공적으로 수행하였다. 연소시험 결과 연소압을 고정한 후 혼합비를 증가시킨 경우 연료 및 산화제 유량계수는 일정한 것으로 나타났으며, 혼합비를 고정한 후 연소압을 증가시킨 경우에도 연료 및 산화제 유량계수는 변함이 없는 것으로 파악되었다. A subscale gas generator was designed and manufactured to understand a reason for increased pressure drop of liquid oxygen injectors observed in a technology demonstration model of a 75 ton-class gas generator. A total of 6 hot-firing tests were successfully performed including experimental conditions of design and off-design points. The hot-firing results showed that discharge coefficients of fuel and liquid oxygen remained constant as the mixture ratio varied at a fixed chamber pressure. At a fixed mixture ratio, it was also found that discharge coefficients of fuel and liquid oxygen was constant as the chamber pressure was increased.
김문기(Munki Kim),임병직(Byoungjik Lim),강동혁(Donghyuk Kang),안규복(Kyubok Ahn),김종규(Jong-Gyu Kim),최환석(Hwan-Seok Choi) 한국추진공학회 2011 한국추진공학회 학술대회논문집 Vol.2011 No.11
축소형 가스발생기를 제작하여 연소시험을 성공적으로 수행하였으며 분사기의 형상 변화에 따른 유량계수의 영향을 파악하였다. 연소시험 결과 연료 및 산화제 분사기의 유량계수는 혼합비와 연소압에 상관없이 거의 일정하였으며, 모든 시험조건에서 연소 불안정은 발생하지 않았다. The hot-firing tests of a subscale gas generator were successfully performed to investigate the effect of injector shape variation on its discharge coefficient. The test results showed that discharge coefficients of fuel and liquid oxygen injectors remained nearly constant irrespective of the mixture ratio or the chamber pressure. In all experimental conditions, the combustion instability was not observed.