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김상덕(Sang-Deok Kim),변영섭(Young-Seop Byun),송준범(Jun-Beom Song),이병언(Byoung-Eon Lee),송우진(Woo-Jin Song),김정(Jeong Kim),강범수(Beom-Soo Kang) 한국항공우주학회 2009 韓國航空宇宙學會誌 Vol.37 No.3
근거리 감시정찰을 수행할 수 있는 헬리콥터형 무인항공기를 개발하였다. 임무수행 가능성을 검토한 결과 전동 모터로 구동되는 동축반전 헬리콥터형 비행체가 선정되었다. 자동비행을 위해 상용 자동비행장치와 무선통신 모뎀이 채택되었고, 공중촬영을 위한 CCD카메라가 탑재되었다. 완성된 비행체는 수동 비행시험을 통해 성능을 검증하였으며, 자동비행장치 탑재 후 점항법 비행을 통해 임무수행이 가능함을 확인하였다. 본 논문에서는 동축반전 무인항공기의 개발을 위한 설계 및 체계종합 전 과정에 관하여 기술하였다. The rotorcraft-based unmanned aerial vehicle(UAV) capable of performing close-range surveillance and reconnaissance has been developed. Trade studies on mission feasibility led to the adoption of a coaxial rotorcraft with twin rotors counter-rotating in one axis and driven by electric motors. A commercial off-the-shelf flight control computer(FCC) and a radio frequency modem were adopted for autonomous navigation. In order to achieve an aerial view, commercial charge-coupled device camera was also integrated into the vehicle. The performance of the completed vehicle was proved with manual flight test, and mission capability was verified through waypoint navigation flight after being equipped with FCC. This paper treats the whole process of design and system integration for development of the coaxial rotorcraft UAV.
소윤석(Younseok So),우성필(Seongphil Woo),이광진(Kwangjin Lee),유병일(Byungil Yoo),김진형(Jinhyung Kim),조황래(Hwangrae Cho),방정석(Jeongsuk Bang),한영민(Yeoungmin Han) 한국추진공학회 2016 한국추진공학회 학술대회논문집 Vol.2016 No.12
본 논문에서는 9톤급 다단연소사이클 엔진용 산화제 과잉 예연소기 분사기 설계 및 수류시험 결과에 대해 기술하고자 한다. 총 3 종류의 동축 와류 분사기를 설계하고 각 종류마다 12개의 분사기를 제작하였다. 연료 접선홀 직경은 모두 동일하며, 산화제와 연료가 연소되어 발생하는 기체 산화제와 냉각 채널에서 배출되는 액체 산화제 모멘텀의 비에 따라 산화제 과잉 예연소기 분사기의 연소에 어떠한 영향이 있는지를 연구하기 위해 산화제 접선홀의 직경을 다르게 제작하였다. 추후에 산화제 과잉 예연소기를 이용한 파워팩과 연소시험을 통해 검증될 예정이다. 수류시험 결과, 연료 유량은 설계차압을 기준으로 목표값에 도달하였지만, 산화제 유량은 설계 차압을 기준으로 목표값을 넘어서는 결과를 보였다. This paper is described for results of cold flow test and design of injectors for oxidizer-rich preburner applied with 9tonf-class staged combustion engine cycle. The 3 types of coaxial swirl injectors are designed and manufactured. The diameters of fuel tangential hole are same with 0.7 mm. The diameters of oxidizer tangential hole are difference because of momentum ratio which is Gox oxidizer momentum occurred by combustion from mixing of fuel and oxidizer in the injector chamber and Lox oxidizer momentum from cooling channel. It will be confirmed by the powerpack and combustion test of oxidizer rich preburner in later. The results of cold flow test, the fuel flowrate is proper for differential pressure at design point but the oxidizer flowrate is over for differential pressure at design point.
수소 생산을 위한 동축원통형 수증기 개질기의 성능 및 열유속에 대한 수치해석 연구
박준근(Joonguen Park),이신구(Shinku Lee),배중면(Joongmyeon Bae),김명준(Myoungjun Kim) 대한기계학회 2009 大韓機械學會論文集B Vol.33 No.9
Heat transfer rate is a very important factor for the performance of a steam reformer because a steam reforming reaction is an endothermic reaction. Coaxial cylindrical reactor is the reactor design which can improve the heat transfer rate. Temperature, fuel conversion and heat flux in the coaxial cylindrical steam reformer are studied in this paper using numerical method under various operating conditions. Langmuir-Hinshelwood model and pseudo-homogeneous model are incorporated for the catalytic surface reaction. Dominant chemical reactions are assumed as a Steam Reforming (SR) reaction, a Water-Gas Shift (WGS) reaction, and a Direct Steam Reforming (DSR) reaction. Although coaxial cylindrical steam reformer uses 33% less amount of catalyst than cylindrical steam reformer, its fuel conversion is increased 10 % more and its temperature is also high as about 30 degree. There is no heat transfer limitation near the inlet area at coaxial-type reactor. However, pressure drop of the coaxial cylindrical reactor is 10 times higher than that of cylindrical reactor. Operating parameters of coaxial cylindrical steam reformer are the wall temperature, the inlet temperature, and the Gas Hourly Space Velocity (GHSV). When the wall temperature is high, the temperature and the fuel conversion are increased due to the high heat transfer rate. The fuel conversion rate is increased with the high inlet temperature. However, temperature drop clearly occurs near the inlet area since an endothermic reaction is active due to the high inlet temperature. When GHSV is increased, the fuel conversion is decreased because of the heat transfer limitation and short residence time.
변영섭,송우진,김정,강범수 한국항공우주학회 2011 한국항공우주학회 학술발표회 논문집 Vol.2011 No.11
This paper describes the procedure of development of a coaxial rotorcraft micro air vehicle for indoor surveillance and reconnaissance mission. The survey to provide a guide for preliminary design were conducted based on commercial off-the-shelf platform, and the rotor performance was estimated by the simple momentum theory. The modified fuel balance method which is adoptable for electric powered vehicle was applied to determine the initial size of the micro air vehicle, and it was optimized with sequential quadratic method. The developed vehicle shows stable handling quality with manual flight test in indoor situation. 본 논문에서는 실내 감시정찰 임무를 위한 동축반전 헬리콥터형 미세비행체의 개발과정을 기술하였다. 기본설계 방향을 제시하기 위해 상용 비행체의 제원을 조사하였고, 간단한 운동량 이론에 의해 공력 성능이 예측되었다. 미세비행체의 초기 사이징을 위해 전동 모터로 구동되는 비행체에 적용 가능한 수정된 fuel balance 기법이 적용되었고, sequential quadratic 기법에 의해 최적설계가 수행되었다. 개발된 비행체는 실내에서 수행된 수동조종 시험에서 안정된 조종성을 나타내었다.
실내감시정찰용 동축반전 헬리콥터형 미세비행체 설계 및 제작
변영섭(Youngseop Byun),신동환(Donghwan Shin),안진웅(Jinung An),송우진(Woojin Song),김정(Jeong Kim),강범수(Beomsoo Kang) Korean Society for Precision Engineering 2011 한국정밀공학회지 Vol.28 No.12
This paper is focused on the procedure of the development of a micro air vehicle which has vertical take-off and landing capability for indoor reconnaissance mission. Trade studies on mission feasibility led to the proposal of a coaxial rotorcraft configuration as the platform. The survey to provide a guide for preliminary design were conducted based on commercial off-theshelf platform, and the rotor performance was estimated by the simple momentum theory. To determine the initial size of the micro air vehicle, the modified conventional fuel balance method was applied to adopt for electric powered vehicle, and the sizing problem was optimized with the sequential quadratic programming method using MATLAB. The designed rotor blades were fabricated with high strength carbon composite material and integrated with the platform. The developed coaxial rotorcraft micro air vehicle shows stable handling quality with manual flight test in indoor situation.
고한별(Han Byeol Ko),강효림(Hyo Lim Kang),한승호(Seung Ho Han) 대한기계학회 2022 大韓機械學會論文集B Vol.46 No.4
다양한 공정 라인에서 유량 및 압력을 조절하는 목적으로 제어 밸브가 활용되고 있다. 글로브 밸브는 제어 밸브의 고유유량특성에서 밸브의 개도율에 따라 유량계수가 등비율로 나타나며 개폐의 신속성은 물론 정교한 유량조절도 가능하여 광범위하게 사용되고 있으나, 낮은 개도율에서 유로의 변화가 심한 단점을 갖고 있다. 이를 보완하기 위해 구조가 단순하고 스템의 1/4 회전으로 완전 개폐가 기능한 볼 밸브가 제어 밸브로 주목받고 있다. 그러나 볼 밸브는 개도가 유로의 측면에서 시작되고, 고유유량 특성이 등비율로 나타나지 않아 정교한 유량조절이 어렵다. 본 연구에서는 동축 반전 장치가 삽입된 볼 밸브를 제안하였으며, 형상개념설계를 통해 개도 시 유로가 중앙에서 시작할 수 있도록 하였다. 아울러 전산유체해석을 통해 제어 밸브에서 요구되는 개도율에 따른 등비율의 고유유량특성을 만족하는지 여부를 확인하였다. 해석 결과 개도율 20~100% 변화에 따라 유량계수 C<SUB>v</SUB>는 1.05~110.49 범위에서 지수함수적으로 증가하여 등비율 특성이 나타났다. 또한 유량제어용으로 사용되는 기존의 V-port 볼 밸브와의 C<SUB>v</SUB> 비교를 통해 유량제어 밸브로서의 가능성을 검토하였다. A control valve that can precisely control flow rate and pressure is used in various process lines. The globe valve has been widely applied as a control valve owing to fast opening, closure, and precise flow control. Furthermore, an equal flow coefficient percentage of a globe valve can be provided as the inherent flow characteristics required for a typical control valve. The flow path, however, changes rapidly at a low opening rate. Recently, a ball valve was considered as a control valve owing to its simple structure and requires only a quarter-turn of the stem to be fully opened and closed. There are disadvantages to these characteristics, such as opening starting at the side of the flow path, and the inherent flow characteristics do not appear in an equal flow coefficient percentage. In the present study, a coaxial counter-rotating ball valve was proposed through a structure conceptual design, in which opening can start at the center of the flow path. The computational fluid dynamics analysis was carried out to assure whether the equal percentage of flow coefficient was satisfied due to change of the opening rate. The flow coefficient C<SUB>v</SUB> with a range of 1.05~110.49 was increased exponentially at the opening rate of 20~100%. In addition, the availability of the proposed vale as a flow control valve was reviewed by comparing C<SUB>v</SUB> with a V-port ball valve commercially used.
산화제 과잉 예연소기용 분사기 설계 및 수류 시험 결과
소윤석(YoonSeok So),우성필(SeongPil Woo),이광진(Kwang-Jin Lee),유병일(ByungIl Yu),김진형(Jinhyung Kim),조황래(Hwangrae Cho),방정석(Jeongsuk Bang),한영민(YeongMin Han) 한국추진공학회 2018 한국추진공학회지 Vol.22 No.1
This paper presents the design and cold flow test results of oxidizer-rich preburner injectors for a 9 tonf-class staged combustion engine cycle. Three types of coaxial swirl injectors were designed, and 12 injectors were designed for each type. The diameters of the fuel tangential holes are identical. The diameters of the oxidizer tangential holes were varied to investigate the influence of combustion in the oxidizer-rich preburner according to the momentum ratio of the gas oxidizer generated from combustion in the injector chamber and liquid oxidizer through the cooling channel. It will be verified through a powerpack and combustion test using an oxidizer-rich preburner. In the cold flow test, the fuel flow rate and oxidizer tangential hole flow rate reached the target value based on the designed differential pressure.