• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2005.11a
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• pp.93-99
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• 2005

Performed were 2-phase numerical studies on two types of fuel atomizers, plain orifice and pressure swirl atomizer. In case of plain orifice, cavitation model was applied so that discharge coefficient, cavitation size, and magnitude of cavitation region characterized and compared with experimental results for several different pressure enforced to the orifice. In case of swirl atomizer, VOF model was applied to analyze air core size, spray angle, and wall pressure distributions with comparison of experimental results.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 1999.10a
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• pp.2-2
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• 1999

본 연구에서는 액체 로켓용 추진제 분사기로 많이 활용되는 충돌형 분사기중에서 2중 충돌(F-O-O-F)형 분사기에 대한 미립화 특성을 파악하였다. 액적의 크기를 측정하기 위하여 위상/도플러 입자분석기를 사용하였으며, 모의 추진제로 물을 사용하였다. 모의 추진제의 운동량비와 압력 강하량 변화에 따른 2중 충돌(F-O-O-F)형 분사기의 미립화 특성과 크기분포에 대하여 고찰하였다. 분사기 면으로부터 100mm 떨어진 단면에서 산화제/연료의 운동량비가 MR=1.19에서 MR=6.48까지 증가함에 따라 액적크기(SMD)는 감소하였으며, 액적크기(SMD)가 운동량비(MR)에 대하여 SMD= 193.480+15.687MR-5.036M$R^2$+0.415MR$^3$와 같은 관계식에 근사되었다 또한, 연료와 산화제의 압력강하량이 증가할수록 액적크기(SMD)가 감소하였다. 충돌 분무유동장의 액적크기 분포는 Rosin-Rammler 분포함수와 Upper-limit분포함수 모두에 대하여 잘 일치하고 있다. 본 연구의 결과는 액체 로켓용 충돌형 분사기의 초기 설계단계에서 유용하게 사용될 수 있을 것이다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.699-703
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• 2017

Numerical simulations of closed-type and open-type single injectors were conducted to investigate the flow characteristics of a swirl-coaxial injector used in a liquid rocket engine. Numerical analysis was conducted using a commercial program ANSYS FLUENT. The injectors has three models with different recess length. Numerical analysis was conducted to investigate the variation of the flow characteristics of the injector when the flow condition were changed. It was also compare and analyzed with experimental results. The results obtained from the numerical simulation show that the difference between the inlet pressure and the discharge coefficient is not significant.

• Journal of the Korean Society of Propulsion Engineers
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• v.24 no.6
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• pp.126-142
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• 2020

This study aims to provide basic design data for a pintle injector and its combustion device through case study on the research and development of combustion devices to which a liquid-liquid pintle injector was applied. From data analysis, it was possible to provide the initial dimension of the combustion chamber and pintle injector based on the engine thrust, and the geometric characteristics of the high-efficiency injector. In addition, the pintle tip heat damage prevention mechanism and materials, face-shutoff pintle injector implementation method, and central propellant selection criteria were summarized. Theses results will be used as basic data for the design criteria of an initial pintle injector combustion device.

• Aerospace Engineering and Technology
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• v.4 no.2
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• pp.135-141
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• 2005

The procedure of conceptual and detailed design of sub-scale combustor using bipropellant swirl or impinging injector with external or internal mixing for a liquid rocket engine are described in this paper. The sub-scale combustor uses liquid oxygen(LOx) and kerosene as propellants and has a injector head, an ablative material combustor wall and a water cooled nozzle. The injector head has LOx manifold, fuel manifold, fire face plate, one center swirl or impinging injector and 18 main swirl or impinging injectors.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2005.11a
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• pp.407-410
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• 2005

Acoustic coupling between combustion chamber and gas-liquid scheme injectors are studied numerically in liquid rocket engine adopting linear acoustic analysis. The injectors can play a role as half-wave resonators. The combustion chamber with numerous injectors shows peculiar acoustic coupling with the injectors. As the injector length approaches a half wavelength or the original tuning length, new injector-coupled acoustic modes show up in the chamber and thereby, the acoustic-damping effect of the tuned injectors is appreciably degraded.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 1999.04a
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• pp.2-2
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• 1999

액체추진제 로켓엔진에서 분사기의 미립화 및 혼합 특성과 그에 따른 연소 특성은 성능과 안정성을 결정하는 중요한 파라미터이며 분사기는 제한된 설계 조건하에서 최대의 열방출율을 발휘하도록 설계되어야 한다. 여기서 연소효율은 연료와 산화제의 혼합특성과 충돌 분무의 미립화의 정도에 의해 결정되므로 충돌 분무 유동성의 혼합, 미립화 특성과 이에 따른 인조성능 특성을 명확하게 밝힘으로써 최대 엔진성능을 위한 설계가 가능하게 된다. 분사기의 설계에는 분사요소형태, 분사공의 형상 및 유동시스템 등이 포함되며 특히 분사요소 형태의 선택에는 추진제, 연소실냉각방법, 연소실 형상, 자동조건 및 엔진의 수명 등이 중요한 제한조건으로 고려된다. 이런 형태의 분사 요소들 중, 충돌형 분사기는 저장성 추진제를 사용하는 중, 저추력의 액체추진제 로켓엔진에 주로 사용된다. 이 분사형태는 미립화 성능이 높지 않고, 분사공 직경 및 운동량비에 따른 혼합성능이 만감하며 blow apart 등에 의한 열부하 혹은 안정성에 대한 문제가 있으나 양호한 혼합효율, 신뢰성과 제작의 용이함으로 인하여 광범위하게 사용된다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2005.11a
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• pp.247-250
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• 2005

In the case of appling a unielement injector developed for a full scale liquid rocket combustor, a operating condition or configuration of the injector is changed by combustion pressure, arrangement and injector quantity of a full scale liquid rocket combustor. In order to verify application, swirl coaxial injectors propelled by jet-A1 and liquid oxygen are tested at different conditions of a combustion pressure, a flowrate and an injector length. As a test result, the application of the present swirl coaxial injectors is excellent because an efficiency of a characteristic velocity is increased at the each test condition beyond that variation of dynamic pressure intensity is small.

• Proceedings of the KSME Conference
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• 2005.11a
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• pp.207.2-207.2
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• 2005

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.4
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• pp.395-402
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• 2010

Baffle injectors are protruded into the combustion chamber and form an anti-pulsating baffle to prevent high-frequency combustion instabilities in transverse modes. Being exposed to a high heat-flux environment, the baffle injector has self-cooling passages through which kerosene is convected and heated. The baffle injector with 20 spiral cooling channels has been developed and successfully applied to 30 $ton_f$-class combustors without any performance loss due to an additional cooling. In this work, numerical analysis of conjugate heat transfer in baffle injectors with various cooling channel designs has been performed in order to reduce the fabrication cost which would be considerably increased for the 75 $ton_f$-class combustor. Prior to the application to a full-scale combustor, the thermal durability of the modified design has been verified through the subscale hot-firing tests.