• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.11a
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• pp.153-156
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• 2009

The pitch and yaw axis controls of Kick Motor, KLSV-I second propulsion system, was provided by the flexible seal that consists of alternate laminate of natural rubber and composite reinforcements between forward and aft ring. A hydrostatic actuating test has been conducted to evaluate a performance of the manufactured flexibke seal before it is assembled at the nozzle. Through the tests, we have verified an actuation torque and axial displacement of the flexible seal according to pressure variation. The actuation torque and axial displacement of all flexible seal is shown below 60kgf-m/deg at without pressure and 6mm at MEOP respectively.

• Journal of Aerospace System Engineering
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• v.12 no.3
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• pp.1-8
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• 2018

The fuel pump, which is used for an aircraft, was first developed in Korea through the Civil-Military Dual Components Development Program. The BLDC motor type, which is superior to the DC brush motor when considering efficiency, endurance, and explosive environmental characteristics, was applied to the fuel pump given its capacity and operating condition. The magnetic flux of the permanent magnet was analyzed based on the magnet flux density equation, using the Maxwell equation and the environmental condition. The motor performance, according to the load, was analyzed using the finite element method in order to design validation. The motor assembly was developed by designing the motor drive and the EMI filters. The performance test results of the motor assembly for the fuel boost pump were consistent with the analysis.

• Journal of the Korean Society of Propulsion Engineers
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• v.8 no.2
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• pp.73-84
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• 2004

In general, static firing test is conducted before flight in order to obtain data such as thrust. pressure, temperature and strain, which show the characteristics of rocket motors. But the measured thrust of the obtained data is especially distorted by the effects of dynamic characteristics of thrust stand so that it is difficult for us to determine the exact value of peak thrust and rising time etc., which represent the performance of rocket motor. This paper, therefore. verified the causes of distortion of measured thrust, and proposed the theoretical method to estimate the true thrust from the distorted thrust. And also the proposed method was applied to virtual thrust stand using computer simulation, and showed good result. As a result of that, the proposed method was proven to be valid and applicable to estimate distorted thrust.

• Proceedings of the KIPE Conference
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• 2017.07a
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• pp.391-392
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• 2017

최근 자동차 산업의 연구개발의 핵심화두는 효율성 제고 및 NVH(Noise, Vibration, Harshness) 개선에 있다. 특히나 많은 부품들의 개발에 있어서 운전자의 운전 편의성을 높이는 성능적인 지표 외에도 운전자가 느끼는 소음, 이상 진동에 대한 감성성능에 대한 소비자의요구도 높아지고 있다. 이러한 경향에 맞추어 자동차 각 부분의 소음저감, 효율향상을 고려한 설계에 대한 연구가 활발해지고 있다. 많은 자동차 부품들에 모터가 사용되고 있으며, 특히 차량용 쿨링팬의 경우 모터를 사용하여 차량 운행 시 발행하는 (배터리의 온도를) 적절한 수준으로 유지시켜주거나 친환경 자동자차 배터리를 쿨링 하는 역할을 한다. 대다수의 쿨링팬 모터로 BLDC모터가 많이 사용되며 이는 전통적인 제어 방법인 구형파제어를 사용하고 있다. 본 논문에서는 저전압 배터리의 전원을 사용하여 BLDC 쿨링팬을 안정적으로 구동할 수 있는 제어기를 개발하였고, 소음저감 및 높은 효율을 위하여 정현파로 제어하는 기법을 적용하였다. 개발된 시작품의 성능 시험을 통해 그 결과를 검증하였다.

• Proceedings of the Korean Nuclear Society Conference
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• 2001.10a
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• pp.353.2-353
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• 2001

• Journal of computational fluids engineering
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• v.15 no.4
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• pp.109-114
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• 2010

In a fan design, CFD analysis, which is very useful for mechanical design relating to the heat and fluid dynamics, is one of the most popular tools. However, since the CFD analysis is conventionally carried out with the constant fan speed condition, the speed change, induced by the air flow rate and motor characteristics, is hardly modeled. And, consequently, the remarkable difference exist between analysis and experimental results. In this paper, we has proposed a method of setting the varying fan speed as a boundary condition considering air flow rate and motor torque-speed characteristics. The effectiveness of the proposed method is verified by comparison with experimental results.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 1997.11a
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• pp.14-14
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• 1997

추진제의 노화 못지 않게 점화제의 노화도 추진 기관 성능에 큰 영향을 미칠 것으로 예측된다. 따라서 10년 이상 경과된 활성 모터에서 점화기를 분해하여 노화에 의한 점화제의 성능 변화를 알아보았다. 분석에 사용한 점화제는 II-D Bi-Convex형상의 B-KNO$_3$ 펠렛으로 열량, 자동 점화온도, 기계적 물성의 변화를 관찰하였고, 밀폐 용기(Closed bomb)에서 연소시험을 통하여 노화에 따른 점화알약의 압력변화를 측정하고 이론 값과 비교하였다. 또한 비활성 모타를 이용한 연소시험으로 점화기의 점화지연시간, 최대 압력, 최대 압력 도달시간 등을 측정하고 이론식과 비교하여 노화에 의한 변화를 관찰하였다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.44 no.11
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• pp.981-988
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• 2016

Dynamometer is a device for testing the performance of the brake and it is composed of a test zone, the mechanical inertia zone, the electric motor and the control zone. Hybrid dynamometer is a way to compensate for the loss of mechanical inertia in accordance with the brake operation by using an electric motor to reduce the size of the mechanical inertia with the advantage that can be tested in the relatively small size of the mechanical inertia and low cost. In this paper, design the proper size of hybrid dynamometer in the laboratory level with the space constraints, analysed the effect of critical parameter on the braking performance of hybrid dynamometer such as changing the friction coefficient. With this study, could get the results of guideline to judge the poor friction material by measuring the torque of the electric motor to compensate the energy loss due to a reduced mechanical inertia.

• The KSFM Journal of Fluid Machinery
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• v.12 no.6
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• pp.26-32
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• 2009

We have constructed loading apparatuses to electrical motor with a powder brake and a oil pump for load test of a several ten kilowatt-motor and performed load test with two motors. On operating the loading apparatus with a oil pump, temperature of the oil may excessively increase and fail to operate due to dynamic energy loss of equipment in oil loop. In order to control the oil temperature, factors of the energy loss were analyzed and the quantitative loss was calculated. Load tests of motors with two loading apparatuses constructed were successfully performed and strengths of each apparatus come out on operating.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.05a
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• pp.183-186
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• 2008

Both structural analysis and hydraulic test have been conducted to confirm the burst characteristics of filament wound solid motor case. Failure criteria have been defined with bursting above 150% of MEOP and failure in the cylinder. The results of analysis showed that filament fiber in the cylinder should be broken at about 2088psig. From a hydraulic test the same failure mode and the level of 2200psig of burst pressure have been proved. With these results, it is verified that a filament wound case meets burst requirements.