• Journal of the Korean Society of Propulsion Engineers
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• v.15 no.5
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• pp.19-26
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• 2011

In order to investigate the effect of fuel injection hole configuration within the scramjet combustor, experiment and quasi-one-dimensional analysis was performed. And the results were compared with experiment and analysis result which were performed in 2008 with same facility and test condition. Fuel injection hole size was decreased and quantity was increased. However the depth of fuel penetration and flow quantity of fuel were maintained. As a test result, combustion performance was increased significantly with no-cavity injector and slightly with plain-cavity. However, combustion performance with zigzag-cavity was decreased.

• Journal of the Korean Society of Propulsion Engineers
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• v.8 no.1
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• pp.54-60
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• 2004

Experimental study on combustion characteristics of double swirl coaxial injectors has been conducted for the assessment of critical injector design parameters. A reusable, subscale thrust chamber has been fabricated with a water-cooled copper nozzle. Two different configurations of injectors have been tested for the understanding of the effects of recess length on high pressure combustion. Clearly, the recess length drastically affects the combustion efficiency and hydraulic characteristics of an injector. Internal mixing of propellants in an injector with recess number of two increases a combustion efficiency and reveals sound combustion although a pressure drop required for the same amount of mass flow rates increases compared with an injector of recess number of one.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.1
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• pp.45-49
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• 2006

The flow around a foil with waterjet was investigated using the two-frame PIV(CACTUS 3.1) system. After separation, unsteady recirculation & reattachment region was shown as a result at reading edge. Separation area was decreased to 1/3 more by waterjet system with coanda effect. Angle of attack and waterjet velocity was a variable in the experiment. Each parameters was controlled to $0^{\circ}{\sim}35^{\circ}$ and 0[m/s]${\sim}$9.2[m/s]. The separation of flow appearanced at first when the angle of attack is $17^{\circ}{\sim}18^{\circ}$. However, according to grew up of velocity, beginning of the separation was delayed. In this experiment, vortex and separation region was disappeared by blown when each parameters are low level, and separation controlled more certainly.

• 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.

• 한국벤처창업학회:학술대회논문집
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• 2022.04a
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• pp.17-24
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• 2022

국내 창업연구 결과에 따르면 사내벤처 기업의 생존률 및 성과가 일반 창업기업 대비 더 높게 나타난다는 연구결과들이 제시되고 있다. 이에 우리 정부는 2017년부터 사내벤처 및 분사창업기업 육성을 위한 지원제도를 운영하고 있으며, 본 연구에서는 이러한 정부의 개입이 분사창업기업의 창업과 성장에 미치는 영향 관계를 분석하는 것을 목적으로 하고 있다. 본 연구의 대상자는 2019년 1차년도 사내벤처 육성프로그램에 참여한 7개의 기업 중 11개의 분사기업팀을 대상으로 하였으며, 주된 영역은 (1)분사 칭업자의 특성에 따른 기업가적 의도 및 (2) 모기업의 지원정책, (3) 정부의 정책 개입에 따른 분사창업과의 관계를 규명하고자 하였다. 3개월의 이노베이션 부트캠프 과정 이후 2022년까지 해당기업의 CEO 인터뷰 및 기사를 통해 추적한 결과, 사내벤처팀 모두 모기업의 지원정책과 본인의 업무를 기반으로 창업을 시작하였으며, 모기업 및 유통파트너를 첫 소비자로 하는 경우가 다수를 차지하였다. 모기업은 재정직 지원 제공하는 한편, 정부에서 요구한 '실패시 재입사 가능'의 조항을 준수하고 있었으며 이러한 정부의 정책개입은 중소기업의 사내벤처제도에 긍정적인 영향을 미치고 있음을 확인할 수 있다. 본 연구를 통해 우리나라 정부의 사내혁신을 통한 혁신창업 활성화에 이론적, 실무적, 정책적 제안을 제시하고자 한다.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.4
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• pp.417-422
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• 2010

Low temperature diesel combustion was achieved via a combination of late injection timing ($8.5^{\circ}$ CA BTDC to $0.5^{\circ}$ CA BTDC) and heavy exhaust gas recirculation (37% to 48%) with ultra low sulfur Swedish diesel fuel in a 1.7L common rail direct injection diesel engine. When injection timing is retarded at a certain exhaust gas recirculation rate, the particulate matter and nitrogen oxides decease simultaneously, while the hydrocarbon and carbon monoxide increase. Hydrocarbon speciation by gas chromatography using a flame ionization detector reveals that the ratio of partially burned hydrocarbon, i.e., mainly alkenes increase as the injection timing is retarded and exhaust gas recirculation is increased. The two most abundant hydrocarbon species are ethene which is a representative species of partially burned hydrocarbons, and n-undecane, which is a representative species of unburned hydrocarbons. They may be used as surrogate hydrocarbon species for performing a bench flow reactor test for catalyst development.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.37 no.12
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• pp.1079-1089
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• 2013

The flow characteristics in a solid particle incinerator are investigated numerically for high burning rate of wastes. The studied incinerator employs both a swirl flow used in the furnace of powerplants and a design concept applied to a rocket combustor. As the first step, the non-reactive flow field is analyzed in the incinerator with primary and secondary injectors through which solid fuel and air are injected. The deflection angle of a primary injector, inclination angle of a secondary injector, and gap between the two types of injectors are selected as design parameters. The swirl number is adopted for evaluating the degree of swirl flow and estimated over wide ranges of three parameters. The swirl number increases with deflection angle, but it is affected little by inclination angle. Recirculation zones are formed near the injectors, and their size affects the swirl number. The swirl number decreases with the zonal size of recirculation. From the numerical results, the design points can be found with strong swirl flow.

• 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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• 2006.05a
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• pp.288-293
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• 2006

The combustion performances and characteristics of the subscale liquid rocket combustion chamber are discussed in this paper. Subscale combustion chamber is composed of mixing head, ablative cooling cylinder, and water cooling nozzle. The mixing head has eighteen coaxial swirl injectors and one center coaxial swirl injector for ignition. The mixing heads employing the injectors of low different recess length are considered in this paper. The results of the firing test, comparison of performance, and characteristics of static and dynamic pressures of the four different mixing heads are described. The characteristics of combustion at design and of design points are also discussed.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2005.11a
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• pp.335-340
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• 2005

A study on the variation of combustion characteristics by injector geometries was conducted. Coaxial swirl injectors were used. Existence of swirl chamber and variation of a nozzle length become key parameters. Injectors were identified as open, closed and mixed type by existence of swirl chamber. Variation of nozzle length was made extruding the both nozzle along the axis while other design parameters remain the same. A uni-element combustor with ablative material liner and a water cooled nozzle made by oxygen free copper with outer stainless steel casing were used.