• Journal of the Institute of Electronics Engineers of Korea CI
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• v.41 no.2
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• pp.103-112
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• 2004

In this paper, we propose the automatic control algorithm of torque/pipejacking thrust and slurry charging/discharging pressure in the microtunneling system to assist operators assuring the quality of microtunneling construction. To develop this algorithm, we analyze the microtunneling system which is manually controlled by expert and design fuzzy controller. warning system, and halt sensing system The proposed automatic tunneling algorithm shows good tunneling results comparable with those of experts.

• Journal of Korean Tunnelling and Underground Space Association
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• v.5 no.3
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• pp.269-278
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• 2003

Microtunneling techniques play a crucial role in the construction of pipelines. In this paper shows the automatic tunneling algorithm of microtunneling system by using fuzzy logic technology to assist operators assuring the quality of microtunneling construction. To have effective output value of fuzzy controller, we slightly modified the conventional defuzzificaton methods. The proposed automatic tunneling algorithm shows good tunneling results comparable with those of experts.

• Aerospace Engineering and Technology
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• v.4 no.1
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• pp.49-56
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• 2005

Hot firing performance test of hydrazine decomposition catalyst used for monopropellant thruster of the satellite and the launch vehicle was performed. Test equipment for catalyst test was developed in collaboration with Hanwha Corp., reaction delay time, catalyst activity and granule stability of the catalyst firing performance were measured and analyzed with the equipment. In addition, the current development of prototype catalyst is introduced.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2006.05a
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• pp.181-184
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• 2006

We successfully completed the development test for a 10-ton thrust liquid rocket engine using LOX+LNG (Liquefied Natural Gas, or Methane) with a high performance turbopump system. Resulting from the success of the regenerative-cooling capability using LNG, high pressure-generating capability and gas-generating performance, etc, methane engine with the product name CHASE-10 will be commercialized in the near future.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.254-257
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• 2011

Two types of thrusters(Descent Control Thruster (DCT) for reducing landing speed and Attitude Control Thruster (ACT) for attitude control) are mounted on the propulsion system of Ground test model lunar lander. In this paper, plume impingement effect and ground effect between DCT Modules are analyzed using numerical method when the impact occurred close to the ground.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.826-827
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• 2008

선형전동기는 위치 및 속도 제어기구로 빠른 속도와 강한 추력 정확한 위치 제어가 가능하다. 선형전동기의 성능 향상 및 소형화를 위해서는 추력의 최대화가 요구되는데, 일반적으로 추력을 계산하는 방법으로 유한요소법, 등가자기회로망법 등이 있다. 본 연구에서는 유한요소법을 이용하여 정자장 해석인 정특성과 과도해석인 동특성을 분석하였다. 향후 정특성과 동특성의 결과를 통해서 시제품의 실험결과와 비교 분석하여 동특성해석에 대한 검증을 수행할 것이다.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.150.2-150.2
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• 2012

로켓 엔진용 짐벌 마운트는 발사체 발사 후 자세 제어를 위해 발사체와 엔진사이에 장착된 TVC(Thrust Vector Control) 구동기의 작동으로 짐벌 운동을 수행하며 기구학적으로 자세 제어를 하는데 있어 매우 중요한 역할을 하는 요소이다. 이러한 짐벌 마운트는 엔진 추력을 발사체에 전달하는 기능 이외에 지정된 위치에 엔진을 고정시키는 역할과 위치 고정 후 발사체 단과 엔진의 정확한 추력 전달을 위한 기계적 불일치 보정 기능, 짐벌 구동에 대한 피봇 기능을 동시에 수행하여야 하는 복합적인 기능을 가지고 있다. 특히, 이중에서도 물리적으로 고 추력의 하중을 전달하는 요소로서 충분한 강도와 강성을 지녀야 하므로 본 연구에서는 이와 관련된 초기 설계 요구도 분석을 바탕으로 설계 규격에 부합하는 짐벌 마운트의 구조적 검토를 통해 로켓 엔진용 짐벌 마운트 설계 형상을 개념적으로 제시하였다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.05a
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• pp.53-56
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• 2009

In this paper, performance evaluation of catalyst for hydrogen peroxide thruster with drying condition is described. Platinum was selected as a catalyst, and alumina of pellet type was chosen as a catalyst support. Evaporation method known as general method for catalyst production was used to make the catalyst. From previous experiments, it is favorable during catalyst making process that solution of active material has low pH level. Therefore, some kinds of low pH level solution had been tested. The drying temperatures are 25, 50, 70, and $90^{\circ}C$. From experimental results, it shows better performance that drying temperature was $90^{\circ}C$ since the catalyst particle could not be crystallized but be evenly spreaded out due to the rapid evaporation of solvent.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.388-391
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• 2017

In this study, heat transfer analysis of variable thrust control system have been conducted by using commercial CFD code and FEM code. We Carried out computational fluid dynamics analysis to obtain the temperature and convective heat transfer coefficient of hot gas of variable thrust control system. Data are used as boundary condition for heat transfer analysis using mapping method. Temperature of O-ring for sealing was predicted

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.10
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• pp.955-965
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• 2010

The MH-75 propeller for the MAV propulsion is designed using a free vortex design method which considers design parameters such as the hub-tip ratio, the twist angle distribution, the maximum camber location and the chord length of the propeller blade. Aerodynamic characteristics of the MH-75 propeller are predicted by changing the flight speed using the frequency domain panel method. And, the thrust characteristics of the MH-75 propeller are measured using the balance system of the subsonic wind tunnel for the validation of numerical results. The performance characteristics of the MH-75 propeller satisfied with design requirements. Numerical results of the MH-75, which are predicted by the frequency domain panel method, are more agree with experimental results compare with XFOIL.