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문근환,문희장,최주호,김진곤,Moon, Keun-Hwan,Moon, Hee-Jang,Choi, Joo-Ho,Kim, Jin-Kon 한국항공운항학회 2016 한국항공운항학회지 Vol.24 No.4
In this study, reliability prediction of the ignition system of hybrid rocket is performed. The FMECA is preceded to the reliability prediction. To this end, the ignition system is divided into 5 components and 19 potential failure modes. The failure cause and effects are identified and criticality analysis is carried out for each failure mode, in which the criticality number is estimated using the failure rate databases. Among the numbers, the failure modes and components with higher criticality and severity are chosen and allocated with higher weighting factor. The reliability predictions are performed using the failure rate databases, from which the current ignition system is found to satisfy the target reliability.
A Probabilistic based Systems Approach to Reliability Prediction of Solid Rocket Motors
문근환,강진혁,김동성,김진곤,최주호 한국항공우주학회 2016 International Journal of Aeronautical and Space Sc Vol.17 No.4
A probabilistic based systems approach is addressed in this study for the reliability prediction of solid rocket motors (SRM). To achieve this goal, quantitative Failure Modes, Effects and Criticality Analysis (FMECA) approach is employed to determine the reliability of components, which are integrated into the Fault Tree Analysis (FTA) to obtain the system reliability. The quantitative FMECA is implemented by burden and capability approach when they are available. Otherwise, the semiquantitative FMECA is taken using the failure rate handbook. Among the many failure modes in the SRM, four most important problems are chosen to illustrate the burden and capability approach, which are the rupture, fracture of the case, and leak due to the jointed bolt and O-ring seal failure. Four algorithms are employed to determine the failure probability of these problems, and compared with those by the Monte Carlo Simulation as well as the commercial code NESSUS for verification. Overall, the study offers a comprehensive treatment of the reliability practice for the SRM development, and may be useful across the wide range of propulsion systems in the aerospace community.
하이브리드 로켓 모터의 신뢰성 분석을 위한 FMEA 및 FTA
문근환,김동성,최주호,김진곤,Moon, Keun Hwan,Kim, Dong Seong,Choi, Joo Ho,Kim, Jin Kon 한국항공운항학회 2013 한국항공운항학회지 Vol.21 No.4
In this study, the FMEA and FTA for reliability analysis of hybrid rocket motor are performed, that was designed in the Hybrid Rocket Propulsion Laboratory of Korea Aerospace University. In order to carry out these analyses the structure of the hybrid rocket motor is hierarchically divided into 36 parts down to the component level and FMEA is carried out with 72 failure modes. Reliability is assessed based on the FMEA, and the results are used in the FTA to evaluate the overall system reliability. In the FMEA, the relationship between the cause and failure modes, effects and their risk priorities are evaluated qualitatively. 27 failure modes are chosen as those with the critical severity that should be improved with priority. As a result of the FMEA / FTA study, a series of design or material changes are made for the improvement of reliability.
몬테 카를로 시뮬레이션을 이용한 하이브리드 로켓의 신뢰성 분석
문근환,김완범,이정표,최주호,김진곤,Moon, Keunhwan,Kim, Wanbeom,Lee, Jungpyo,Choi, Jooho,Kim, Jinkon 항공우주시스템공학회 2013 항공우주시스템공학회지 Vol.7 No.4
In this study, probabilistic reliability analysis was conducted for hybrid rocket performance using Monte-Carlo Simulation. For the accuracy, reliability analysis was performed with experimental data. To simplify the analysis process, the oxidizer was supplied with constant pressure, so that pressure variation with time can be eliminated. And time-space averaged regression rate model was used. The regression rate is obtained with a series of experiments. For reliability analysis of thrust, constant exponent of regression rate is assumed that has probabilistic character. So, the efficiency of characteristic velocity has also probabilistic values. As a results, probability distribution of the thrust is obtained by Monte-Carlo simulation using random samples of the input parameter and validated under the 95% confidence level.
비연소성 다이아프램을 적용한 하이브리드 연소기의 연소 특성 연구
문근환(Keunhwan Moon),김학철(Hakchul Kim),이선재(Sunjae Lee),최원준(Wonjun Choi),이정표(Jung-pyo Lee),문희장(Heejang Moon),성홍계(Honggye Sung),김진곤(Jinkon Kim) 한국추진공학회 2011 한국추진공학회 학술대회논문집 Vol.2011 No.5
비연소성 다이아프램을 장착한 하이브리드 연소기에서 후퇴율 및 연소효율 특성에 관한 연소 실험을 수행하였다. 실험결과 다이아프램을 장착한 경우 후퇴율 및 연소효율이 증가하였으며, 연료포트 직경과 다이아프램 내경의 단차가 클수록 후퇴율 및 연소효율이 증가하였다. 또한 다이아프램으로 인한 연소율 변화를 표현할 수 있는 후퇴율 관계식을 제안하였다. The hybrid combustion experiments using non-combustible diaphragm were performed for characteristic of regression rate and combustion efficiency. Results of experiments using diaphragm were showed that the regression rate and efficiency were increased. In addition, the larger difference between fuel grain port and diaphragm port increase the regression rate and efficiency. The modified regression rate equation was proposed with the port area ratio of fuel and diaphragm.
문근환(Keunhwan Moon),조정태(Jungtae Cho),김수종(Soojong Kim),이정표(Jungpyo Lee),김학철(Hakchul Kim),오지성(Jisung Oh),문희장(Heejang Moon),성홍계(Honggye Sung),김진곤(Jinkon Kim) 한국추진공학회 2010 한국추진공학회 학술대회논문집 Vol.2010 No.5
하이브리드 로켓에서의 고체 연료의 연소 현상을 가시화하기 위하여 장치를 제작하였다. 가시화 장치는 평판 하이브리드 연소기 시스템, 점화 시스템, 산화제 공급 시스템, 데이터 획득 및 제어 시스템, 연소 가시화 측정 장비로 구성되었다. GOX 산화제와 HDPE, Paraffin-LDPE Blending, Paraffin 연료를 이용하여 연소 가시화 시험을 수행하였고, 수치적으로만 연구되어 왔던 연소실 내의 연소 현상을 가시화 할 수 있었으며, 화염의 형성 및 용융성 연료의 액적 비산 현상을 관찰 할 수 있었다. The visualization device for hybrid rocket is fabricated to investigate the combustion phenomena. Visualization device were composed with ignition system, oxidizer supply system, control system and data acquisition system, combustion visualization system. GOX as oxidizer and HDPE, Paraffin-LDPE Blending, Paraffin sd were used. As results, combustion phenomena and fuel droplet entrainment were observed.
추력 1000 kgf급 하이브리드 로켓(KHyRoc-Ⅱ)의 개발
문근환(Keunhwan Moon),오지성(Jisung Oh),이선재(Sunjae Rhee),최원준(Wonjun Choi),김학철(Hakchul Kim),이정표(Jungpyo Lee),문희장(Heejang Moon),성홍계(Honggye Sung),김진곤(Jinkon Kim) 한국추진공학회 2012 한국추진공학회 학술대회논문집 Vol.2012 No.5
본 연구에서는 추력 1000 ㎏f 급 하이브리드 로켓 (KHyRoc-Ⅰ)의 지상 연소 실험을 수행하였다. 지상 연소 실험 결과 약 700 ㎏f의 추력을 획득하였으며, 비행 궤적 계산 결과 최대 고도 12.5 ㎞로 계산 되었다. 그리고 KHyRoc-Ⅰ의 큰 L/D비(28)로 인한 구조 안전성의 문제점을 보완하기 위해, 직경 250 ㎜의 알루미늄 seamless tube를 사용하여 L/D비가 작은(18.3) KHyRoc-Ⅱ를 재설계하였다. 내탄도 해석을 통하여 추력 900 ㎏f 하이브리드 로켓 엔진을 설계하였으며, 비행 궤적 계산 결과 최대 고도는 약 7.4 ㎞로 계산되었다. In this study, the hybrid rocket was developed that has a thrust of 1000 ㎏f level. The static fire test was shown that the thrust was 700 kgf level and trajectory was predicted by the maximum altitude of 12.5 ㎞. The L/D ratio of KHyRoc-Ⅰ has 28, but the KHyRoc-Ⅱ were designed the small L/D ratio(18.3) using the seamless aluminium tube(Diameter : 250 ㎜). And KHyRoc-Ⅱ has a thrust of 900 ㎏f level, that is designed with internal ballistics and trajectory was predicted by the maximum altitude of 7.4 ㎞.
고체 로켓 추진 기관의 신뢰성 분석을 위한 준-정량적 FMECA
문근환(Keun Hwan Moon),김진곤(Jin Kon Kim),최주호(Joo Ho Choi) 대한기계학회 2015 大韓機械學會論文集A Vol.39 No.6
본 연구에서는 고체 로켓 추진 기관의 신뢰성 분석을 위해 준-정량적 FMECA를 수행하였다. 준-정량적 FMECA는 고장모드 및 영향 분석(FMEA)과 치명도 분석(CA)를 포함하는 분석 기법으로서, FMECA 수행을 위해서 FMEA는 고체 로켓 추진 기관을 43개의 부품으로 나누어 각 부품에 대하여 도출된 총 137개의 고장모드에 대해 수행하였다. 또한 일부 고장모드의 고장률 데이터를 이용하여 치명도 분석을 수행하였다. 준-정량적 FMECA 수행을 통하여 고체 로켓 추진 기관의 각 부품에서 발생 할 수 있는 잠재적 고장모드와 고장원인 및 영향을 분석, 정리할 수 있었으며, 우선적인 개선 조치가 필요한 중요 고장모드를 확인할 수 있었다. In this study, semiquantitative failure mode, effects, and criticality analysis (FMECA) for the reliability analysis of a solid rocket propulsion system is performed. The semiquantitative FMECA is composed of failure mode and effects analysis (FMEA) and criticality analysis (CA). To perform FMECA, the structure of the solid rocket propulsion system is divided into 43 parts down to the component level, and FMEA is conducted at the design stage considering 137 potential failure modes. CA is then conducted for each failure mode, during which the criticality number is estimated using the failure rate databases. The results demonstrate the relationship between potential failure modes, causes, and effects, and their risk priorities are evaluated qualitatively. Additionally, several failure modes with higher criticality and severity values are selected for high-priority improvement.
원통형 멀티포트 그레인에 스월 인젝터를 적용한 하이브리드 로켓의 연소 특성 연구
문근환(Keunhwan Moon),오지성(Jisung Oh),조정태(Jungtae Cho),이정표(Jungpyo Lee),문희장(Heejang Moon),성홍계(Honggye Sung),김진곤(Jinkon Kim) 한국추진공학회 2010 한국추진공학회 학술대회논문집 Vol.2010 No.11
본 연구는 하이브리드 로켓 연소에서 원통형 멀티 포트 그레인과 스월 인젝터 적용 시 각각 후퇴율 증가의 장점을 취합하고자 수행하였으며, 연료 포트 수와 스월 인젝터의 배치에 따른 후퇴율 변화에 대한 실험을 수행 하였다. 실험 결과 멀티 포트 그레인에 샤워 헤드 형태의 인젝터를 적용한것 보다 스월 인젝터를 적용한 경우의 후퇴율이 증가되는 것을 확인 할 수 있었다. In this paper, a study for hybrid rocket combustion with cylindrical multi-port grain and swirl injector was performed to take advantage of regression rate. Change of the regression rate in the multi-port grain the placement of a swirl Injector experiments were performed. The results of multi-port grain using swirl injector were showed that the regression rate was increased compare with the shower head type injector.