• 한국연소학회:학술대회논문집
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• 한국연소학회 2014년도 제49회 KOSCO SYMPOSIUM 초록집
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• pp.153-156
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• 2014

This study was aimed to assess combustion stability for coaxial swirl injector and FOOF impinging injector which would be candidates in liquid rocket engine combustors. Simulating combustion tests under atmospheric condition have been conducted by gaseous oxygen and the mixture of methane and propane, using two actual injectors. By analyzing the measured dynamic pressure signals, we have evaluated the combustion stability margin of both injectors by drawing a stability map.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2006년도 제26회 춘계학술대회논문집
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• pp.135-140
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• 2006

충돌형(FOOF) 분사기의 불안정 영역을 결정하기 위해 질소분사 음향시험을 수행하였다. 파이프와 오리피스 형상을 가지는 분사기 내 산화제 부분에서 유동속도에 비례하고, 비정상적으로 jumping하는 특정 주파수를 가지는 whistling이 발생한다. 동일한 조건의 연소시험과 비교해 본 결과 whistling 현상은 연소현상에는 영향을 주지 않는다. 질소분사 음향시험과 연소시험에서 얻은 연소실 내 1T1L mode의 damping factor를 비교하여 불안정 영역을 구해보면, 비슷한 조건에서 불안정 영역을 가진다. 이것은 유동의 충돌, 혼합에 의한 유동불안정 현상이 연소시험에서 연소불안정을 발생시키는 주요한 인자임을 의미 한다.

• 한국연소학회지
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• 제22권1호
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• pp.46-52
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• 2017

High-frequency combustion instabilities may occur during the development of feasible engine combustors. These instabilities can result in irreparable damages to the wall of combustors or the degradation of engine performance. So, it is essential to identify injectors that have high stability characteristics during the early stages of development. The objective of present study was to assess the stability of coaxial injectors and an impinging injector with different recess lengths in order to develop stable injectors optimally. Stability margin was evaluated based on the distance from operating condition to the unstable regions. A simulating combustion test method was used to analyze the stability of injectors. A small-scale combustion chamber was designed to simulate the first tangential acoustic mode of the actual combustor. Gaseous oxygen and a mixture of methane and propane were used as simulant propellants to satisfy their flow similarity to the actual propellants of a combustor in a liquid rocket combustor. The results indicated that injectors having small recess lengths showed relatively large combustion stability margins. For the injectors of large recess lengths, instability regions with large and super-large amplitude oscillations were observed. Thus, injector with shorter recess lengths had a higher stability than that of longer one due to the different mixing processes.

• 대한기계학회논문집B
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• 제24권5호
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• pp.718-724
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• 2000

A model for depicting the rocket engine combustion process is presented and several experiments near a design point are provided with a FOOF type of unlike impinging injector for a propellant combination of Jet A-1 fuel and liquid-oxygen. The model is based on the assumption that the vaporization is the rate-controlling combustion process. The effects of initial drop size and initial drop velocity are systematically shown and discussed. It is seen that in the midst of considered parameters the change of initial drop size is more sensitive to the performance. The proposed model describes qualitative trends of combustion process well despite of its simplicity.

• 한국추진공학회지
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• 제3권3호
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• pp.1-8
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• 1999

$H_2$O/Kerosene을 사용하여 Unlike 충돌형 인젝터(FOOF형)에서 산화제와 연료의 운동량비 변화에 따른 혼합효율을 측정하였다. 모의 추진제의 운동량비 1.5(총혼합비 1.89)에서 혼합성능은 최대 값을 나타내었으며 모의 추진제의 실험결과는 실제 추진제인 LOX/Kerosene에 적용하여 혼합특성속도 효율을 예측하였다 연구 결과 혼합특성속도 효율은 운동량비 2.0에서 최대 값을 나타내었다. 이러한 예측은 실제 연소실험을 통하여 얻어진 연소효율과 약간의 차이는 있으나 초기설계자료로서 충분한 가치가 있는 것으로 판단된다.

• 한국연소학회지
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• 제5권1호
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• pp.43-53
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• 2000

Experimental studies on determination of the supply leading time of propellants to combustion chamber have been made to stably and efficiently guarantee the ignition process with liquid rocket engine. The propellant used is a Jet A-1 as fuel and a liquid oxygen as oxidizer. Unlike impinging FOOF type of injectors are arranged radially and the designed O/F ratio is 2.34. The present experiment program also includes the stability on the quadlet type of ignitor using the triethylalumimum as an ignition source and injector life tests. Experimental results clarifies that the propellant supply through LOx leading to combustion chamber is proper for stable ignition and combustion processes based on the fuel and oxidizer manifold pressures, combustion chamber pressure, and the variation of flame length from the nozzle exit with lapse time, and shows that the leading supply time of propellants affects the engine performance little. The effect of positioning cooling holes is remarkable to protect the injector face.

• 한국연소학회:학술대회논문집
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• 한국연소학회 1999년도 제19회 KOSCO SYMPOSIUM 논문집
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• pp.209-217
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• 1999

A model for depicting the rocket engine combustion process is presented and basic experiments near a design point are provided with a FOOF type of unlike impinging injector for RP-I fuel and liquid-oxygen. The model is based on the assumption that the vaporization is the rate-controlling combustion process. The effects of initial drop size and initial drop velocity are systematically shown and discussed. It is seen that in the midst of considered parameters the change of initial drop size is more sensitive to the performance. The proposed model describes qualitative trends of combustion process well despite of its simplicity.

• 대한기계학회논문집B
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• 제24권11호
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• pp.1457-1463
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• 2000

Experimental studies on determination of the supply leading time of propellants to combustion chamber have been made to stably and efficiently guarantee the ignitions process with liquid rocket engine. The propellant used is a Kerosene as fuel and a liquid oxygen as oxidizer. FOOF type of three injectors are set with an angle of 135。 and the combustion chamber pressure is 200psi. The present experiment program also includes the stability on the quadlet type of ignitor using the triehylaluminum (TEAL) as an ignition source. Experimental results clarifies that the propellant supply through LOx leading to combustion chamber is proper for stable ignition and combustion processes based on the fuel and oxidizer manifold pressures, combustion chamber pressure, and the variation of flame length from the nozzle exit with lapse time, and shows that the leading supply time pf propellants effects the engine performance little.