• 한국추진공학회지
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• 제18권1호
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• pp.58-64
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• 2014

다양한 홀 크기를 갖는 오리피스를 이용하여 1, 2단 챔버를 구성하는 공압 모사모터를 제작하였다. 오리피스의 면적과 노즐 목 면적비에 따라 2단 챔버 작동 시 1단 챔버와 압력차가 발생한다. 이 압력차는 실제 추진기관 성능에 영향을 미치므로 오리피스 면적 및 설계에 대한 고찰이 필요하다. 2단 챔버 작동 시 1단 챔버 압력은 오리피스 크기 및 1단 챔버 형상에 따른 와류형성으로 에너지 손실이 발생한다. 본 논문에서는 상용 CFD(Computational Fluid Dynamics) 프로그램(ANSYS FLUENT V14.5)를 이용하여 유동을 모사하였다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2013년도 추계학술대회 논문집
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• pp.815-824
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• 2013

Pneumatic exciters can be good replacements of electrodynamic, piezoelectric and hydraulic exciters owing to simple structure and large exciting force. One problem to be solved is a slow response caused by compressibility of air. Desirable frequency response characteristics of exciter are constant magnitude and zero degree phase, because users want no time delay between input signal and output force. For this reason, frequency range of pneumatic exciters is limited about 0~1 Hz. Therefore, expansion of frequency range is an important issue when designing the pneumatic exciter. In this paper, the pneumatic exciter which has same structure with active pneumatic isolator is dealt with. The dynamic characteristics are presented, and its limitation of expanding frequency range is shown based on analytical studies. Then the pneumatic exciter with dual-chamber is suggested to overcome this problem. Based on simulation study, a design method is presented.

• 한국소음진동공학회논문집
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• 제23권10호
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• pp.909-919
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• 2013

Pneumatic exciters can be good replacements of electrodynamic, piezoelectric and hydraulic exciters owing to simple structure and large exciting force. One problem to be solved is a slow response caused by compressibility of air. Desirable frequency response characteristics of exciter are constant magnitude and zero degree phase, because users want no time delay between input signal and output force. For this reason, frequency range of pneumatic exciters is limited about 0~1 Hz. Therefore, expansion of frequency range is an important issue when designing the pneumatic exciter. In this paper, the pneumatic exciter which has same structure with active pneumatic isolator is dealt with. The dynamic characteristics are presented, and its limitation of expanding frequency range is shown based on analytical studies. Then the pneumatic exciter with dual-chamber is suggested to overcome this problem. Based on simulation study, a design method is presented.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 춘계학술대회논문집
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• pp.1112-1118
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• 2007

This paper investigates the performance of an electromagnetic type active control engine mount (ACM) recently developed in the laboratory. The ACM employs the basic structure of the conventional hydraulic engine mount of which upper chamber is connected to a dual magnet electromagnetic actuator. The actuator, that essentially replaces the existing decoupler of the conventional passive hydraulic engine mount, actively controls the upper chamber pressure. Using the linearized ACM model incorporated with the actuator dynamics, we suggest an optimal design of ACM, maximizing the actuator efficiency as well as the vibration isolation efficiency.

• 한국군사과학기술학회지
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• 제6권4호
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• pp.113-123
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• 2003

Both numerical analysis and experiment of cold and hot tests were performed to obtain basic design data for the swirl coaxial type Injector and to predict the combustion performance. Mass distribution, mixing distribution, mixing efficiency, characteristic velocity efficiency were measured by the cold tests and numerical analysis using the commercial thermo-hydraulic program. Test and analysis variables were recess, pressure drop, velocity ratio, mixing spray, mixture ratio. Hot tests were performed for the Uni-element injector to compare the performance with the cold test results, and, hot tests for Multi-element injector were performed to compare the performance with Uni-element injector. Designed thrust of the Uni-element injector liquid rocket was 35kgf at sea level and combustion chamber pressure, 20bar. Kerosene and Lox were used as a propellant.