• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2007.11a
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• pp.147-150
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• 2007

In this study, cooling characteristics of combustion gas were investigated by injecting liquid nitrogen into liquid rocket combustion chamber. A injection ring of liquid nitrogen was installed between a combustion chamber and a mixing chamber which was designed for mixing of combustion gas and nitrogen. At first, a ignition test of liquid rocket engine was conducted to verify a stable combustion process and 10 second combustion tests were successfully conducted. The results showed that combustion gas of LRE could be cooled by using liquid nitrogen.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2000.04a
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• pp.30-30
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• 2000

액체로켓엔진의 단일추진제 가스발생기는 연료공급 시스템의 터보펌프를 구동시키기 위한 작동가스 생성을 목적으로 사용된다. 고체추진제 가스발생기와 비교할 경우 작동시간이 보다 길고 연소생성물에 의한 터빈 블레이드의 삭마가 없으며 제어가 용이하므로 초기 액체로켓엔진 개발시부터 사용되어 왔다. 80년대 이후 개발된 액체로켓엔진은 이원추진제 가스발생기 또는 연소가스 FEEDBACK 시스템을 채용하고 있지만 단일추진제 가스발생기는 과산화수소수 또는 하이드라진과 같은 별도의 추진제 공급 시스템을 필요로 하는 단점에도 불구하고 상대적으로 낮은 온도의 무연 작동 가스를 발생하므로 가스발생기 자체를 위한 냉각시스템을 제거 또는 최소화 시켜 간단한 구조로 전체 시스템 설계를 가능하게 하므로 중소형 액체로켓엔진에 사용되고 있다.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.141.1-141.1
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• 2014

오일 증기의 제트를 분사하여 잔류가스를 배기하는 오일확산펌프는, 구조가 간단하여 고장이 적고 저렴하며 소음 및 전기노이즈가 적게 발생하는 많은 장점을 가지고 있다. 그러나 오일의 증기압에 의해 그 도달압력이 10-9 Torr 이상으로 제한되어, 액체질소로 냉각되는 배플형태의 저온 트랩을 사용하지 않는 한 10-10 Torr영역의 초고진공 배기용으로는 사용하지 못하는 것으로 알려져 있다. 유회전펌프로 뒷받침 배기(foreline pumping)하는 700l/s의 배기속도를 가진 오일확산펌프에 300 liter/sec의 컨덕턴스를 가진 액체질소 트랩을 부착하여 메탈 실링을 사용하는 초고진공 챔버를 배기하였다. 액체질소트랩에 액체질소를 투입하면 $1{\times}10-8Pa$이하의 초고진공이 얻어졌으나, 액체질소가 증발하여 트랩의 온도가 상온으로 상승하면 압력도 $1{\times}10-7Pa$ 이상으로 상승하였다. 50 liter/sec의 배기속도를 가진 터보분자펌프로 오일확산펌프를 뒷받침 배기하면 액체질소를 투입하지 않은 상태에서 $5{\times}10-9Pa$이하의 초고진공이 얻어졌으며, 액체질소를 투입하여도 압력은 거의 변화하지 않았다. 잔류가스분석장치로 얻은 잔류가스 성분 스펙트럼은 수소가 잔류가스의 대부분을 차지하는 것을 보여주었다.

• Aerospace Engineering and Technology
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• v.3 no.1
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• pp.205-212
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• 2004

In this paper, to satisfy the temperature requirement of turbopump-inlet condition, the cooling of cryogenic propellant is performed at the simulated suction-line of the Launch Vehicle. The cooling method is by using gas helium injection. This paper investigates the effect of helium injection on liquid nitrogen, which simulates the liquid oxygen. By using helium injection, subcooling of liquid nitrogen can be achieved and in the condition of v/vL≒0.8min-¹ approximately in four minutes subcooling temperature can be achieved.

• Journal of Power System Engineering
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• v.12 no.1
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• pp.28-34
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• 2008

가스-액체 이젝터에 관한 수치해석은 3차원 CFD 모델로 수행하였다. 본 논문에서는 이젝터의 유동특성과 질량전달특성에 대한 작동조건과 이젝터의 기하학적 모형의 영향에 관한 연구를 수행하고자 한다. CFD 결과 실험 데이터에 의하여 검증되었으며, 유동 분석과 이젝터 성능의 예측 또한 실행되었다. 작동상태의 변화는 0.2 $\sim$ 1.2 범위에서 가스-액체 유량비를 변화시킴으로서 주어진다. 혼합관의 $L_M/D_M$이 4 $\sim$ 10의 범위에서 변화를 주었다. CFD 연구는 길이와 직경비가 5.5일 때 체적 유량전달계수는 가스 유량이 증가함에 따라 증가한다는 것을 나타낸다. 동시에 $L_M/D_M$가 4일 때 체적유량전달계수는 기체-액체 유량비가 0.6에서 최대치에 도달한다. 또한, 체적 유량전달계수는 혼합 튜브길이가 증가함에 따라 감소한다.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.10
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• pp.1001-1009
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• 2012

In this study, the cooling characteristics of combustion gas were investigated by injecting liquid nitrogen ($LN_2$) into a liquid rocket combustion chamber, which uses liquid oxygen (Lox) and kerosene as propellants. $LN_2$ injectors and an extended chamber for mixing were installed at the end of the ordinary LRE combustion chamber, and a nozzle was installed after the chamber for mixing. First, an ignition test of the liquid rocket engine was conducted to verify the stable combustion process. Next, a hot firing test was performed step-by-step for safety. Finally, the test was performed for 20 s. The results showed that the combustion gas of the LRE could be successfully cooled by using $LN_2$.

• Journal of the Korean Society of Marine Environment & Safety
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• v.18 no.3
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• pp.279-285
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• 2012

It is necessary to install the inert gas system(IGS) for preventing fire and explosion in LNGC main diesel engine crankcase besides oil mist detector(OMD) unit with $CO_2$ gas injector. Therefore, to design the liquid nitrogen IGS, analytical work is conducted for predicting the heat input load of liquid nitrogen heater with two-phase stratified flow model. This paper also presents the effects of changes in pipe diameter, saturated pressure, and inclination angle by ship's movement on cryogenic two-phase stratified flows. It is found that the stratified model gives reasonable predictions, and the model is effective to predict the heat input load of liquid nitrogen IGS.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.61-64
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• 2017

The gas-generator open cycle is adapted for liquid rocket engine of Korea Space Launch Vehicle-II. The combustion instability can interfere with combustion performance and cause a noise and vibration or carry the potential for serious damage. This study introduces the experience cases of combustion instability in development of the gas generator for liquid rocket engine.

• 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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• 2012.05a
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• pp.52-57
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• 2012

A liquid rocket system consists of a combustion chamber, a gas generator, a turbo pump, and a turbine, etc. Each component is connected by supply components such as valves, pipes, and orifices. Since each component has a combined effect on engine performance, preliminary analysis for overall system must be required before the conceptual design stage. Comprehensive analysis program considered the supply system has not been developed yet. In this paper, a supply component model of the liquid rocket engine has been designed after verification of each component. The gas generator cycle with supply components has been composed. The results of the cycle has been compared to those of the F-1 engine with the representative gas generator cycle.