• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.39 no.9
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• pp.871-876
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• 2011

In this paper, the equilibrium flight conditions of a Korean Traditional Bangpae Kite with low aspect ratio were analyzed by it's aerodynamic data of wind tunnel test. The data of aerodynamic forces and center of pressure of the Kite were used to calculate the relative length of bridles to satisfy the condition of settling the kite to the static equilibrium steady state between ${\theta}=30^{\circ}{\sim}60^{\circ}$. From this equilibrium flight performance analysis, we obtained ($0.88{\pm}0.02$)c of the rear bridle length corresponding to 0.88c of fixed front bridle length. These results were exact agreement with the relative bridle lengths by Korean classical method.

• 유체기계공업학회:학술대회논문집
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• 1997.02a
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• pp.58-73
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• 1997

본 연구는 항공기용 환경제어계통의 시스템관련 제반 기술 및 그 핵심요소인 ACM(Air Cycle Machine)시제기의 개발을 통하여 국내의 여런 항공기개발 사업과 관련하여 급속히 요구되고 있는 항공기의 sub-system을 국산화할 수 있는 기술축적을 목적으로 수행되었다. 본 연구에서는 항공기용 환경제어장치(Environmental Control System : ECS)를 개발대상으로 하여 그 핵심부품인 Air Cycle Machine의 시제품을 순수 국내 기술로 설계/제작하였고, 자체 개발한 성능시험기를 이용하여 성능시험을 수행하였으며 또한 ACM 성능을 검증하기 위하여 기존제품의 자료와 비교하였다. 향후 이 시스템의 상품화를 위해서는 구동축의 무윤활 베어링에 대한 연구가 병행되어 주유동의 오일오염을 국소화시키는 시스템보완이 요구된다. 항공기용 환경제어장치(ECS)의 시스템해석부터 ACM의 공력/구조설계, 제작, 시험등 일련의 개발과정을 통하여 시스템에 대한 해석능력이 향상되었고, 그 핵심요소인 ACM의 순수 국산화개발이 가능하다는 판단을 내릴 수 있었다. 또한, ACM을 구성하고 있는 원심압축기와 반경류형 터빈의 제작 및 시험법은 유사 시스템 및 일반 터보기계류의 국산화개발에 유용하게 이용될 것으로 기대된다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.6
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• pp.536-541
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• 2012

An instrumented pod has been developed to measure the aeroacoustic environment as well as the conventional data such as load, vibration, and aerodynamic heating of fighters during flight tests, confirming to the recently developed external pod design for fighters. This study presents the development of the measurement system in detail, being the first indigenous effort in its kind. The pod was designed to meet the requirements of the MIL-HDBK-1763 and MIL-STD-810 Method 515, which are the base to determine the locations and range of sensors. The Endevco 8510B-2 was selected as the sensor to withstand the harsh environment during the flight tests. In order to assess the integrity of the fabricated pod design, a ground run-up test of a KF-16 has been conducted with the pod installed at Station 5. The test results show that the system works well but the sound level exceeds the predetermined sensor range. The sensor range has been readjusted for flight test performed later.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.32 no.4
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• pp.1-11
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• 2004

Numerical analyses on the aerodynamic characteristics of a counter rotating axial flow fan were conducted for the development of an axial type in-line duct fan. The counter rotating fan has a front rotor and a rear rotor which are counter rotating each other. Blade design of the counter rotating fan was done by extension of design method for axial flow fan which consists of rotor and stator blades. Through flow analysis was performed using matrix method which is applied for flow fields prediction of compressors or turbines. Aerodynamic characteristics and characteristic curves of the counter rotating fan were analyzed by expansion of the frequency domain panel method with duct modeling. Pressure losses were higher at leading edge and hub region of rotor blades. Characteristic curve of the counter rotating fan was overpredicted without consideration of viscous effect.

• Journal of the Korean Society of Propulsion Engineers
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• v.21 no.3
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• pp.18-24
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• 2017

Appropriate selection of the starter is essential for successful starting of the gas-turbine engine. Thus, aerodynamic drag during starting phase should be analyzed to assess the feasibility of the starter. In this paper, aerodynamic drag is modeled based on the speed profile from the engine coast down test, and it is scaled with respect to the target engine by comparing the compressor load. Afterward, the govern equation of the starting phase is developed with the torque model of the starter, and the design scheme to select the feasible starter will be finally suggested. The proposed model of starting phase will be useful to perform a preliminary design of the starting system of the gas-turbine engine.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.47 no.7
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• pp.479-488
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• 2019

A cruise missile uses wings and a jet engine like an airplane to reach the target after cruising a considerable distance. An integrated design of a cruise missile based on radar cross section (RCS) reduction and enhanced aerodynamic performance is indispensable, since it must be able to fly long-distance at subsonic speed without being detected by enemy radar. In this study, we designed a Taurus-type cruise missile and analyzed its RCS and aerodynamic characteristics using the physical optics (PO) technique and the Navier-Stokes CFD code. As a result, we obtained the optimal shape of cruise missile with improved aerodynamic performance and reduced RCS.

• Journal of the Korean Society of Propulsion Engineers
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• v.24 no.5
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• pp.65-76
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• 2020

On the initial design process of a scramjet vehicle such as the trajectory prediction, it is inevitable to estimate the aerodynamic performance of a three-dimensional effect. Despite the necessity of intensive computing for the three-dimensional model, it is inefficient in predicting a wide range of aerodynamic performance. In this study, an engineering model for aerodynamic performance was developed based on two-dimensional computational fluid analysis and linearized supersonic inviscid flow theory. Correspondingly, the three-dimension aerodynamic performance relations are presented based on the two-dimensional results. And the additional three-dimensional computation was performed to evaluate the adequacy for the extended relations.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.12
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• pp.1071-1078
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• 2015

Numerical computations were performed to investigate the effects of pintle stroke, altitude, and bore on the performance of an external pintle thruster. Results show that under-expansion flow occurs always, independent of pintle stroke. An external pintle thruster shows good performance in that it is capable of good amount of thrust control, while aerodynamic loads are increased due to shock waves on the pintle support. When altitude is increased to 20 km, the nozzle exit velocity, Mach number, thrust as well as aerodynamic loads are increased. Bore increases aerodynamic load 5.9%, and therefore pintle shape without bore is preferred for lower aerodynamic load of a pintle in order to actuate the pintle.

• Journal of the Korean Society of Propulsion Engineers
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• v.1 no.2
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• pp.12-21
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• 1997

Nowadays, non-pollution energy sources have been strongly needed because of the exhaustion of fossil fuels and serious environmental problems. Because wind energy can be enormously obtained from natural atmosphere, this type of energy has lots of advantages in a economic and pollution point of view. This study has established the aerodynamic and structural design procedure of the rotor blade with an appropriate aerodynamic performance and structural strength for the 500㎾ medium class wind turbine system. The aerodynamic configuration of the rotor blade was determined by considering the wind condition in the typical local operation region, and based on this configuration aerodynamic performance analysis was performed. The rotor blade has the shell-spar structure based on glass/epoxy composite material and is composed of shank including metal joint parts and blade. Structural design was done by the developed design program in this study and structural analysis, for instance stress analysis, mode analysis and fatigue life estimation, was performed by the finite element method. As a result, a medium scale wind turbine rotor blade with starting characteristics of 4m/s wind speed, rated power of 500㎾ at 12m/s wind speed and over 20 years fatigue life has been designed.

• Journal of Aerospace System Engineering
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• v.11 no.6
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• pp.42-49
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• 2017

A 10kw wind turbine blade aerodynamic design was carried out using the self-developed program AeroDA. The concept, basic shape, and optimization were designed and verified. A performance analysis was carried out and the key factors in each design stage are summarized. In addition, a guide for the placement of cross-section airfoils constituting the blades is presented, and the importance of the stall margin test as a method of verifying aerodynamic design is summarized. In order to verify the design program AeroDA, we compared the results of the performance analysis with a specialized program DNVGL_Bladed.