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음향학적 가진을 통한 Closed-type 스월 인젝터의 동특성 검증
정석규(Seokgyu Jeong),정연재(Yunjae Chung),윤영빈(Youngbin Yoon) 한국추진공학회 2015 한국추진공학회 학술대회논문집 Vol.2015 No.11
Closed-type 스월 인젝터의 다양한 주파수의 외란에 따른 응답 특성을 살펴보고자 하여 실험을 진행하였다. 펄세이터를 사용하여 closed-type 스월 인젝터의 공급부에 압력 섭동을 가하였고, 이에 따른 매니폴드의 압력 및 오리피스에서의 액막 두께를 살펴보았다. 그 결과 본 실험에서 사용된 closed-type 스월 인젝터는 공급계의 압력 섭동에 대해 200 Hz와 700 Hz의 두 개의 피크 주파수를 가짐을 볼 수 있었다. 이에 대한 검증을 위하여 closed-type 스월 인젝터에 음향학적 가진을 주어 인젝터 구조의 공진 특성을 파악해 보았으며 펄세이터 가진 실험과 유사한 주파수 응답 특성을 보임을 발견하였다. 이에 따라 closed-type 스월 인젝터의 동특성에서 발견된 피크 주파수는 인젝터 자체의 구조에 의한 공진주파수와 밀접한 연관이 있음을 밝혀내었다. This experiment was conducted to study the dynamic characteristics of closed-type swirl injector with external pulsations. By using a hydrodynamic mechanical pulsator, pressure pulsation was applied in the manifold of closed-type swirl injector. Pressure at the injector manifold and liquid film thickness at the injector orifice were measured, and as a result, two peak frequencies, 200 Hz and 700 Hz were found. To verify the cause of these peak frequencies, acoustic pulsation was applied to the injector and it was found that the results were similar to pulsator test results. In conclusion, it was found that peak frequencies of the closed-type swirl injector in pulsator test are closely related with the resonant frequencies which are induced by the injector geometry.
정기정(Gijeong Jeong),배진현(Jinhyun Bae),정석규(Seokgyu Jeong),손채훈(Chae Hoon Sohn),윤영빈(Youngbin Yoon) 한국항공우주학회 2017 韓國航空宇宙學會誌 Vol.45 No.7
최근 발사체 시장에 민간주도의 경향이 두드러지게 나타나며, 시장이 포화되어감에 따라 발사비용을 줄이기 위한 노력이 지속되고 있다. 우주탐사 선진국에서는 유인 장거리 우주탐사계획이 추진되고 있다. 산소-메탄의 조합은 기존의 추진제에 비해 효율이 높고 경제적, 친환경적이며 외계행성에서 현지조달이 가능하기 때문에 이러한 경향에 부응하기 위한 가장 적합한 차세대 추진제로서 주목을 받고 있다. 현재 국제정세의 변화와 기업환경 변동에 따라 메탄엔진 개발이 더욱 본격화·가속화되고 있다. 우리나라도 이러한 세계적 흐름에 편승하고 향후 발사체 시장에서 뒤처지지 않기 위해서는 메탄엔진 개발이 필요하다고 판단된다. Recently, there has been a tendency to lead the private sector in the launch vehicle market, and as the market has become saturated, efforts are being made to reduce the launch cost. Advanced countries in space development have promoted manned long-range space exploration plans. As oxygen/methane is more efficient, lower cost, and eco-friendly than typical propellants, and can be produced locally on an alien planet, it is the most suitable next-generation propellant to meet this trend. Now methane engine development is accelerating due to changes in international conditions and corporate environment. It is also expected to develop a methane engine in order to survive in this global trend and to keep up with the launch vehicle market in the future.
발사체 인젝터 특별세션 : Closed-type 스월 인젝터의 스월 챔버 지름에 따른 동특성 변화 연구
정연재 ( Yunjae Chung ),정석규 ( Seokgyu Jeong ),윤영빈 ( Youngbin Yoon ) 한국액체미립화학회 2015 한국액체미립화학회 학술강연회 논문집 Vol.2015 No.-
Studies on the dynamic characteristics of liquid rocket injectors were done worldwide on the basis of theory which were suggested by Bazarov in the late 1970’s.1 The occurrence of combustion instability during the early stage of liquid rocket engine development have made the injector dynamics research to be essential. Since the combustion instability is a complicated problem which involves multi-physical phenomenon, injector dynamics research was focused on the suppressing the symptoms of the combustion instability. However, as the injector dynamics research have achieved progress, the scope of the research has been extended to investigating the injector’s dynamic characteristic itself. In this study, the effect of swirl chamber diameter on the dynamic characteristics of closed-type swirl injector were investigated. A hydro-mechanical pulsator was installed in front of the manifold of the swirl injector which produces pressure oscillations in the feed line. Pressure in the manifold, liquid film thickness in the orifice were measured in order to understand the dynamic characteristics of the closed-type swirl injectors. Amplitudes of pressure in the manifold and liquid film thickness in the orifice were analyzed to verify the peak frequencies. The geometrical cause of each peak frequencies were suggested with experimental results. Figure 1 shows the schematics of open-type and closed-type swirl injectors. The main difference between the two types of swirl injectors is the shape of swirl chambers. The open-type swirl injector has a straight cylinder shape swirl chamber. On the other hand, the closed-type swirl injector has a converging section in the middle of the swirl chamber which accelerates the propellant in angular velocity. In our previous research, the manifold and the tangential entry, which is a converging section, were verified to be the cause of the peak frequency.2 With the open-type swirl injector experiment results, the converging section in the swirl chamber of the closed-type swirl injector were predicted to act as a second geometrical cause of the amplitude peak.
이중 매니폴드 분사기에서 접선방향 유입구의 변화에 따른 분사특성 연구
이인규(Ingyu Lee),정석규(Seokgyu Jeong),윤정수(Jungsoo Yoon),박구정(Gujeong Park),윤영빈(Youngbin Yoon) 한국항공우주학회 2015 韓國航空宇宙學會誌 Vol.43 No.10
가변추력은 대기가 없는 행성에 착륙하거나, 우주공간에서의 도킹에 필수적인 것으로 알려져 있다. 추력을 조절하기 위해 질유량 조절이 가능한 분사기를 사용하는 방법이 대표적으로 알려져 있다. 이에 따라 본 연구에서는 추력조절을 위하여 이중매니폴드 분사기를 사용하여 질유량을 조절하였다. 이중매니폴드 분사기의 주요 변수 중 하나로 판단되는 접선방향 유입구의 개수의 변화에 따른 분사특성을 확인하기 위하여 분무각, 분무패턴을 포함하는 외부유동을 측정하였으며 내부유동 특성 파악을 위한 film thickness를 확인하였다. Thrust variation is an essential parameter in a space mission such as landing on an atmosphereless planet or docking a spacecraft. In order to achieve the thrust variation control, using throttleable injector is a representative and general method. A dual-manifold injector, one of throttleable injectors, was used to control mass flow rate. Five kinds of injectors were designed and investigated in order to compare the spray characteristics of the dual-manifold injector with various tangential entries. Spray angles and patterns were measured to determine external flow characteristics and film thicknesses were measured in order to investigate the internal flow patterns.
정재훈(Jaehoon Jung),정석규(Seokgyu Jeong) 대한기계학회 2022 대한기계학회 춘추학술대회 Vol.2022 No.11
During the late phase of severe accidents, the molten corium may be discharged into the reactor cavity if the lower head of the reactor vessel is failed. The cooling and stabilization of the discharged molten corium in the reactor cavity is important to prevent further accident progression such as molten core-concrete interaction. It is necessary to develop the rapid analysis module for the ex-vessel corium coolability. So, we are developing code of ex-vessel corium coolability analysis (COCCA). In COCCA, it needs to calculate the temperature distribution in the particulate debris bed, to understand the local phenomena and predict the local dryout. A simplified analysis model was developed to determine whether the temperature of particulate debris bed is stabilized. In this study, the simplified analysis model was improved based on the latest experiemtal results performed by KAERI. It was validated using the results of COOLOCE experiments performed by VTT.