• Title/Summary/Keyword: 하이드라진

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Preliminary Design of LEO Satellite Propulsion System (저궤도위성 추진시스템 예비 설계)

  • Yu, Myeong-Jong;Lee, Gyun-Ho;Kim, Su-Gyeom;Choe, Jun-Min
    • Aerospace Engineering and Technology
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    • v.5 no.2
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    • pp.85-89
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    • 2006
  • Propulsion System provides the required velocity change impulse for orbit transfer from parking orbit to mission orbit and three-axis vehicle attitude control impulse. New LEO Satellite propulsion system (PS) will be an all-welded, monopropellant hydrazine system. The PS consists of the subassemblies and components such as Thrusters, Propellant Tank, Pressure Transducer, Propellant Filter, Latching Isolation Valves, Fill/Drain Valves, interconnecting propellant line assembly, and thermal hardwares for operation-environment control of the PS. In this study, preliminary design process of LEO Satellite propulsion system will be summarized.

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달착륙선 지상 시험모델 통합 시험 전 전장계 및 소프트웨어계 최종 점검 환경 구축

  • Gu, Cheol-Hoe;Gwon, Jae-Uk;Ryu, Dong-Yeong;Ju, Gwang-Hyeok;Sim, Eun-Seop
    • The Bulletin of The Korean Astronomical Society
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    • v.37 no.2
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    • pp.169.1-169.1
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    • 2012
  • 한국항공우주연구원에서는 2010년부터 달착륙선 지상 시험모델 개발을 진행하고 있으며 2012년 하반기에 추력 시험을 비롯한 전반적인 전장계 및 소프트웨어계 통합 시험을 계획하고 있다. 본 통합 시험은 탑재 컴퓨터와 VDE를 비롯한 전자 장비가 올바르게 동작하고 있는지 확인하고 소프트웨어가 이들을 잘 제어하고 있는지에 대한 시험 및 하이드라진 추력 시스템에서 본체로부터 명령을 잘 전송받아 적절한 추력을 발생시키고 있는지에 대한 시험 2가지로 크게 구분된다. 통합시험을 통해서 통신 시험용 도구(LECT, Lunar Explorer Communication Tool)에 대한 성능 검증도 같이 수행될 예정이다. 소프트웨어계에 대해서는 각 소프트웨어 모듈에 대한 단위 시험 및 통신 시험용 도구와 연결될 상태에서 통합 성능 시험이 수행될 예정이다. 통합 시험을 앞두고 전장계 및 소프트웨어계의 최종 성능 점검을 위해서 데이터 획득 시스템을 구성하여 입력 및 출력을 모든 채널에 대해서 관찰함으로 다양한 운용 시나리오 하에서 예측된 결과를 보이는지 확인할 예정이며 본 논문에서는 상기 최종 점검 환경에 대한 개념 및 규격, 그리고 제작, 운용 및 시험에 대한 내용을 기술한다.

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A study on Decomposition Characteristics of Hydrazine (하이드라진의 분해특성 연구)

  • Kim Sang Dae;Ahn Hyun Kyoung;Yoon Hyoung Jun;Rhee In Hyoung
    • Proceedings of the KAIS Fall Conference
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    • 2004.11a
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    • pp.255-258
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    • 2004
  • Hydrazine is a weak base and strong reducing agent in the aqueous solution and is primarily utilized as a high-energy rocket propellant and an oxygen scavenger in boiler or feedwater. The objective of this study was to investigate the physicochemical properties and reactions of hydrazine and the catalytic and thermal decomposition by the temperature change. Hydrazine was fast decomposed with the catalyst of lower activation energy and at the higher temperature.

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인공위성의 추진체계 현황 및 전망

  • 이상희;이성태;이용수
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 1995.11a
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    • pp.59-66
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    • 1995
  • 인공위성의 궤도진입, 궤도수정 및 자세제어를 담당하는 추진체계는 위성의 용도와 궤도위치, 자세/궤도제어 방식 등을 고려하여 설계하여야 한다. 현재까지도 널리 사용되고 있는 인공위성 추진체계는 AKM(Apogee Kick Motor)과 단일 추진제 추력기로 구성된 "통상 추진체계"이나 최근에는 AKE(Apogee Kick Engine)과 이원 추진제추력기로 구성된 "통합 추진체계" 그리고 이와 유사한 "완전통합 추진체계", "이중 추진체계" 등이 기술적 선택방안으로 제안되어 일부 적용되고 있는 실정이며 이러한 추진체계의 효과적 실용화를 위해서 단일 추진제(하이드라진) 추력기의 성능향상 및 이원 추진제 엔진과 이원 추진제 추력기의 기술개선 연구가 이루어지고 있다.원 추진제 엔진과 이원 추진제 추력기의 기술개선 연구가 이루어지고 있다.

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Exhaust Plume Behavior Study of MMH-NTO Bipropellant Thruster (MMH-NTO 이원추진제 추력기의 배기가스 거동 해석 연구)

  • Kim, Hyeonah;Lee, Kyun Ho
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.45 no.4
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    • pp.300-309
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    • 2017
  • A spacecraft obtains a reaction momentum required for an orbit correction and an attitude control by exhausting a combustion gas through a small thruster in space. If the exhaust plume collides with spacecraft surfaces, it is very important to predict the exhaust plume behavior of the thruster when designing a satellite, because a generated disturbance force/torque, a heat load and a surface contamination can yield a life shortening and a reduction of the spacecraft function. The purpose of the present study is to ensure the core technology required for the spacecraft design by analyzing numerically the exhaust gas behavior of the 10 N class bipropellant thruster for an attitude control of the spacecraft. To do this, calculation results of chemical equilibrium reaction between a MMH for fuel and a NTO for oxidizer, and continuum region of the nozzle inside are implemented as inlet conditions of the DSMC method for the exhaust plume analysis. From these results, it is possible to predict a nonequilibrium expansion such as a species separation and a backflow in the vicinity of the bipropellant thruster nozzle.

Comparison of Colorimetric Methods for the Determination of Flavonoid in Propolis Extract Products (프로폴리스추출물 제품의 플라보노이드 함량분석을 위한 비색법의 비교)

  • Kim, Eun-Jeong;Lee, Hwa-Jung;Kim, Hye-Jeong;Nam, Hye-Seon;Lee, Mi-Keong;Kim, Hae-Young;Lee, Jin-Ha;Kang, Yun-Sook;Lee, Jong-Ok;Kim, Hee-Yun
    • Korean Journal of Food Science and Technology
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    • v.37 no.6
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    • pp.918-921
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    • 2005
  • Quantitative analysis of flavonoids in commercial propolis extract products were compared by three colorimetric methods; aluminum chloride method, dinitrophenylhydrazine method and aluminum nitrate method, Aluminum nitrate method in Korea Health Supplement Food Code was proved to be specific only for flavones and flavonols same as aluminum chloride method, while dinitrophenylhydrazine method was specific for flavanones and dihydroflavonols. Therefore, the sum of flavonoid contents determined by 2,4-Dinitrophenylhydrazine method and aluminum nitrate method may represent the real content of total flavonoids. As for the 25 commercial propolis extract products examined, the contents of flavonoid varied from 2.15% to 9.53% except for one product.

Development on Metallic Nanoparticles-enhanced Ultrasensitive Sensors for Alkaline Fuel Concentrations (금속 나노입자 도입형의 초고감도 센서 개발 및 알칼라인 연료 측정에 적용 연구)

  • Nde, Dieudonne Tanue;Lee, Ji Won;Lee, Hye Jin
    • Applied Chemistry for Engineering
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    • v.33 no.2
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    • pp.126-132
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    • 2022
  • Alkaline fuel cells using liquid fuels such as hydrazine and ammonia are gaining great attention as a clean and renewable energy solution possibly owing to advantages such as excellent energy density, simple structure, compact size in fuel container, and ease of storage and transportation. However, common shortcomings including cathode flooding, fuel crossover, side yield reactions, and fuel security and toxicity are still challenging issues. Real time monitoring of fuel concentrations integrated into a fuel cell device can help improving fuel cell performance via predicting any loss of fuels used at a cathode for efficient energy production. There have been extensive research efforts made on developing real-time sensing platforms for hydrazine and ammonia. Among these, recent advancements in electrochemical sensors offering high sensitivity and selectivity, easy fabrication, and fast monitoring capability for analysis of hydrazine and ammonia concentrations will be introduced. In particular, research trend on the integration of metallic and metal oxide nanoparticles and also their hybrids with carbon-based nanomaterials into electrochemical sensing platforms for improvement in sensitivity and selectivity will be highlighted.

Performance Analysis and Configuration Design of the Thruster Nozzle for Ground-firing Test and Evaluation (지상연소시험평가용 추력기 노즐의 성능해석과 형상설계)

  • Kam, Ho-Dong;Kim, Jeong-Soo;Bae, Dae-Seok
    • Journal of the Korean Society of Propulsion Engineers
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    • v.16 no.2
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    • pp.10-16
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    • 2012
  • A computational analysis of nozzle flow characteristics and plume structure is conducted to examine performance of the supersonic nozzle employed in a thruster for ground firing test. At first, flow simulations in two-dimensional converging-diverging nozzle are performed for the verification of computational capability as well as turbulence model validity. Axisymmetric converging-diverging nozzles for ground firing test are analyzed with the k-${\omega}$ SST model. A performance penalty caused by flow separation in a diverging section is observed in initially-designed nozzle. The performance could be enhanced by the modification of the diverging section of nozzle contour.

The Response Characteristics of the Hydrogen Peroxide Monopropellant Thruster as Injector and Catalyst Grain Size (인젝터 방식 및 촉매 알갱이 크기에 따른 과산화수소 단일추진제 추력기의 응답 특성)

  • An, Sung-Yong;Park, Dae-Jong;Chung, Seung-Mi;Kwon, Se-Jin
    • Journal of the Korean Society of Propulsion Engineers
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    • v.13 no.1
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    • pp.19-26
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    • 2009
  • The response characteristics of $H_2O_2$ monopropellant thrusters at a pulse mode were presented in this paper. A catalyst bed was fixed to $MnO_2$/$Al_2O_3$ to investigate the thruster design effect to response time. Three different thrusters (50 N class) having different injectors, ullage volumes, catalyst grain sizes, and reactor volumes were prepared to investigate the response characteristics. As a result, the ignition delay, pressure rising and tail-off time of case 2-2 thruster with 16-20 mesh catalyst size were 14, 108, 94 ms respectively, which were comparable to requirement of response time at commercial hydrazine thrusters.

Thrust Performance of 1-lbf Class of Liquid-Monopropellant Rocket Engine (1-lbf급 단일액체추진제 로켓엔진의 추력 성능)

  • 김정수
    • Journal of the Korean Society of Propulsion Engineers
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    • v.8 no.2
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    • pp.32-38
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    • 2004
  • A comprehensive understanding is given for the hot-firing test results, which were obtained throughout the verification program of mono-propellant hydrazine rocket engines (thrusters) producing 0.95 lbf (4.2 N) of nominal steady-state thrust at an inlet pressure of 350 psia (2.41 Mpa). A scrutiny for the engine performance is made in terms of thrust and temperature behavior of steady state firing mode at the given propellant injection pressures: Pinj = 400, 250, 100, and 50 psi. The thrust and specific impulse are compared with a reference performance of 1-lbf standard rocket engines and their normalization procedure is introduced. A practical engineering approach to the data measurement and reduction is addressed, too.