• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.9
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• pp.82-88
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• 2006

In order to effectively reduce thermal loads on regenerative cooled walls, fuel cooling injectors and film cooling devices have often been employed. The present study has established a numerical methodology for prediction of performance and near-wall temperature distribution taking into account the nonuniform mixing due to these additional cooling devices. A correction procedure for main propulsive parameters has also been proposed based on comparison between prediction and experimental data. Under the computational framework of this study, the predicted results were in good agreement with hot-firing test data for a 30 tonf-class full-scale combustor at the design and off-design conditions. As a consequence, the present numerical method is expected to be useful for design and evaluation of regenerative cooled liquid rocket thrust chambers.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2006.05a
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• pp.197-201
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• 2006

In the development process of a fuel-rich gas generator using kerosene and LOx for a 30 tonf class liquid rocket engine, a heat damage occurred at the LOx post of swirl coaxial injectors used in the gas generator and the problem has been examined. To prevent the heat damage, injectors are redesigned to have an increased recess while maintaining internal mixing, which minimizes recirculation region to prevent anchoring of the flame in the recirculation region. The combustion test results of the sub-scale gas generator showed that this scheme can prevent heat damage of the LOx post in the swirl coaxial injectors of the fuel-rich gas generator.

• Journal of the Korean Society of Propulsion Engineers
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• v.11 no.4
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• pp.59-66
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• 2007

In this paper, experimental investigation results of the effect of partial admission ratio on the performance of axial turbine was presented. A supersonic impulse turbine of gas generator cycle liquid rocket engine turbopump was used for the test. for experimental purpose, a nozzle block, in which total 14 number of axi-symmetric convergent-divergent nozzles are arranged circumferentially, was designed and manufactured. Partial admission ratio was controlled by changing the number of active nozzles. High pressure air was used as working medium for the test. The experimental result revealed that the performance of the supersonic impulse turbine does not much affected by the partial admission ratio for supersonic impulse turbine.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.317-317
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• 2008

기존의 초음파 노즐은 단판액츄에이터형 초음파 노즐을 사용하여 연체 연료를 분사하였다. 하지만 단판액추에이터형 초음파 노즐은 300V이상의 고전압을 필요로 하여 소비전력이 높은 단점을 가지고 있다. 하지만 적층액츄에이터형 초음파 노즐은 저전압 구동이 가능하여 낮은 소비전력을 가지며, 단판액츄에이터헝 초음파 노즐보다 우수한 분사특성을 가지고 있는 장점이 있다. 또한 공진형 인버터를 사용하여 초음파 노즐을 구동하는 경우 노즐의 구동 전압을 공진에 의하여 쉽게 얻어질 수 있는 장점과 구동 스위치에 가해지는 전압의 크기가 상대적으로 작게되므로 인버터 구동에 저전압 MOSFET를 사용함으로써 도통손실의 저감 및 구성회로의 저압화 등에 유리한 이점이 있다. 본 연구에서는 적층액츄에이터형 초음파노즐을 개발하고 그에 따른 공진형 인버터를 설계하여 적층엑츄에이터형 초음파 노즐의 분사 시스템을 제안 한다. 또한 실제 액체연료인 경유를 분사하여 전기적특성과 분사특성을 조사한다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2004.10a
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• pp.245-250
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• 2004

The objective of the present study is to conduct model combustion tests for various injectors to identify their combustion stability characteristics. Three different double swirl coaxial injectors with variation of a recess number have been tested for the comparative study of stability characteristic and flame structure. Gaseous oxygen and mixture of gaseous methane and propane have been employed for simulating actual propellants used for a fullscale thrust chamber. Upon test results, the direct comparison between various types of injectors can be realized for the selection of the best design among prospective injectors.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 1999.10a
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• pp.5-5
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• 1999

3단형 과학로켓(KSR-III)의 기본형 및 응용형에 공통으로 사용되는 주엔진은 액체산소를 산화제로, 케로신을 연료로 사용하는 액체추진기관이다. 엔진 기본설계를 통하여 로켓 임무 요구사항에 부합되도록 엔진 각 부분의 기본제원을 설정하였고, 엔진의 형상을 결정하였다. 설계된 엔진의 성능검증 작업은 분사시험용 엔진, 축소형 엔진, 엔지니어링 모델 및 비행시험모델의 설계/제작/시험을 통하여 순차적으로 수행할 계획이다. 본 연구는 3단형 과학로켓 엔진의 기본설계 및 성능검증 계획에 관한 것이다.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 1999.05a
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• pp.177-182
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• 1999

감압증발의 효율을 향상시키기 위한 방법으로 액주내의 기포생성에 의한 자기 미립화를 수반하는 과열액분류의 증발을 분사 감압증발이라고 하며, 특히 적절한 방법으로 액체내에 기포핵을 공급하는 경우에는 매우 좋은 증발성능이 얻어 진다는 것이 보고되어 있다. 따라서 본 연구에서는 온배수를 감압증발시켜 저온저압의 증기를 제조하여 MVR로부터 승온승압에 의해 고온의 증기를 얻기위한 것이 연구의 목적이므로, 증발효율향상을 위해 기포핵 공급용 전해전류장치를 설치하고, 감압증발용의 노즐을 원통형 튜브로 대체하기위해 튜브형 노즐로 부터 과열액을 급격히 감압시켜 자기미립화에 의한 증발을 유도하여 전해전류가 증발효율에 미치는 영향을 실험적으로 연구하고자 작동액체로써 물을 사용하고, 액체온도, 액체유량, 과열도 및 기포핵 공급용의 전해전류량을 변화시켜 실험을 수행하였다.(중략)

• Journal of the Korean Society of Propulsion Engineers
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• v.3 no.2
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• pp.18-24
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• 1999

Liquid ramjet combustor is closely connected with complex phenomena due to a series of processes such as intake air, spray, mixing, and combustion. The present numerical experiments were peformed to investigate these flow characteristics for two and three dimensional liquid ramjet combustor. Grid system was made with three domains: intake region where air is supplied and fuel is injected, combustor and nozzle region, and exit atmosphere region. The numerical results showed that two and three dimensional flow patterns in recirculation region of combustor were significantly different each other and spray model was necessary to predict correctly the chemical reaction flow characteristics. Numerically examined for two different location of fuel injector, one is located on the bottom position of curved intake and the other is located on the top position. We found that bottom position of fuel injector is better than top position because fuel influx to the recirculation region which is need to sustain chemical reaction is more than the latter.

• Journal of the Korean Society of Propulsion Engineers
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• v.26 no.2
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• pp.60-71
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• 2022

The reusable, low-cost launch vehicle development trend in the recent launch vehicle market is being subdivided into several ways, and the throttleable engine is one of them. Plus, several nations have selected methane as a next-generation propellant due to its cleanness. In this research, a throttleable pintle injector using gas methane and liquid oxygen as propellants was developed, followed by its spray and combustion characteristics analysis, including high pressure cold and hot tests. The designed throttleable pintle injector has a double sleeve structure, and its tightness and functionality are confirmed through repetitive atmospheric, high-pressure cold tests, and hot tests. Though some design errors were discovered and a low throttling level was unable to be achieved in the combustion test.

• Journal of the Korean Society of Propulsion Engineers
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• v.11 no.1
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• pp.57-63
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• 2007

The oxidizer-rich preburner is applied to the high efficiency closed cycle rocket propulsion system. This system is generally operated on oxidizer-fuel mixture ratio over than 50. The spray quality and mixing performance are very important for stable combustion of this preburner. This paper presents basic design concept and spray characteristic of the oxidizer-rich preburner injector and this result could be applied to the development of the oxidizer rich preburner system.