• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 1995.11a
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• pp.59-66
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• 1995

인공위성의 궤도진입, 궤도수정 및 자세제어를 담당하는 추진체계는 위성의 용도와 궤도위치, 자세/궤도제어 방식 등을 고려하여 설계하여야 한다. 현재까지도 널리 사용되고 있는 인공위성 추진체계는 AKM(Apogee Kick Motor)과 단일 추진제 추력기로 구성된 "통상 추진체계"이나 최근에는 AKE(Apogee Kick Engine)과 이원 추진제추력기로 구성된 "통합 추진체계" 그리고 이와 유사한 "완전통합 추진체계", "이중 추진체계" 등이 기술적 선택방안으로 제안되어 일부 적용되고 있는 실정이며 이러한 추진체계의 효과적 실용화를 위해서 단일 추진제(하이드라진) 추력기의 성능향상 및 이원 추진제 엔진과 이원 추진제 추력기의 기술개선 연구가 이루어지고 있다.원 추진제 엔진과 이원 추진제 추력기의 기술개선 연구가 이루어지고 있다.

• Bulletin of the Korean Space Science Society
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• 2002.10a
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• pp.37.2-37
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• 2002

• 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 Aerospace System Engineering
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• v.16 no.4
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• pp.1-9
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• 2022

A design factor analysis was conducted to reduce the thrust reduction in the off-design, due to the driving of the aerospike pintle nozzle. The close (NPR 100) as well as the open (NPR 11) stroke were fixed, as under-expansion conditions. The pintle contour, pintle head radius (R), cowl angle (θ), and cowl exit length (L) were selected as design factors. The change in thrust was analyzed, using a verified numerical analysis technique. First, the pintle head radius and the length of the cowl exit had little influence on the thrust. The cowl angle changed the mass flow rate by affecting the effective nozzle throat area, and created a reverse pressure gradient at the cowl exit. As a result of applying the dual aerospike contour, it was confirmed that the thrust in the design-off increased by approximately 1.2%, compared to the reference case and by approximately 3.4% compared to the worst case.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.05a
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• pp.141-144
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• 2008

Atomization characteristics and spatial distribution of the spray emanating from an injector of liquid-propellant thruster are investigated by using dual-mode phase Doppler anemometry (DPDA). Spray characteristic parameters such as the mean velocity, Sauter mean diameter (SMD), and velocity fluctuation are measured at various locations along the spray axis as well as on the radial direction. Those data are quantified in radial profile and also used to scrutinize the correlation between diameter and turbulence intensity of spray droplets. For the better visual grasp, dynamic behavior of spray droplets along the spray stream is presented through the velocity vectors projected on the plane of geometric axis of nozzle orifice and radial coordinate.

• Journal of the Korean Society of Propulsion Engineers
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• v.12 no.5
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• pp.9-17
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• 2008

Pseudo-3D spatial distribution of spray droplets is investigated by using Dual-mode Phase Doppler Anemometry (DPDA) in order to examine the disintegration and spreading behavior of spray exiting from liquid-propellant thruster injector. Spray injected from nozzle orifice with length-to-diameter ratio ($L/d_o$) of 1.67 and under the injection pressure of 27.6 bar is aligned to the vertical. Vertical and horizontal mean velocities of droplets, Sauter Mean Diameter (SMD), and volumetric flux decrease as droplets travel from center/upstream toward outer region/downstream of spray. Although the distribution of spray characteristic parameters is symmetric against the geometric axis of nozzle orifice, their absolute values are asymmetric.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.05a
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• pp.133-137
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• 2010

A dual pulse solid rocket motor has several advantages compared to the single one. The range and the terminal velocity of the guided missile can be remarkably increased by the application of the pulse separation device(PSD) to the solid rocket motor which resulted in appropriate thrust distribution. In this study, the subscale dual pulse solid rocket motor with the bulkhead type PSD was designed, manufactured, and fire-tested. The bursting pressure, thermal characteristics, and the structural safety of the PSD were obtained by the tests and the results will be applied to the design of full-scale dual pulse rocket motor.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.11a
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• pp.113-116
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• 2008

Pseudo-3D Spatial distribution of spray droplets is investigated by using Dual-mode Phase Doppler Anemometry (DPDA) in order to examine the disintegration and spreading behavior of spray exiting from liquid-thruster injector. Spray injected from nozzle orifice with length-to-diameter ratio $(L/d_o)$ of 1.67 and at the injection pressure of 27.6 bar is aligned to the vertical. Vertical and horizontal mean velocities of droplets, Arithmetic Mean Diameter (AMD), Sauter Mean Diameter (SMD), and volumetric flux decrease as droplets travel from center/upstream toward outer region/downstream of spray.

• Journal of the Korean Society of Propulsion Engineers
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• v.25 no.1
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• pp.29-41
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• 2021

The PID controller with fin angle and thrust as control input was designed based on the aerodynamic data of scramjet system. Flight simulation following a given trajectory which strike the target point after climb and cruise with constant dynamic pressure was conducted. After that, the required thrust for the climb and cruise was calculated and the required fuel flow rate for the hydrogen fuel dual mode scramjet combustor was analyzed. The combustor analysis of this study which conducted on integrated model of independently developed inlet, combustor, nozzles and external aerodynamic models, laying the foundation for the integrated design of the air breathing hypersonic system.

• Journal of the Korean Society of Propulsion Engineers
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• v.18 no.6
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• pp.59-67
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• 2014

Acceptance level random vibration and life firing test for development model of 1 N-class monopropellant thruster have been performed. From the results of random vibration, the natural frequency of the dual thurst module composed of 1 N-class development model thrusters was higher than the part level requirement(>100 Hz) and the structural robustness was verified. Thrust decrease of steady sate was below 7% and thrust instability was within ${\pm}5%$ in the life firing test using over 20 kg propellant throughput. The computerized tomography for catalyst bed showed a less than 7% of catalyst loss and it revealed the design appropriateness of the current thruster development model.