• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.205.2-205.2
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• 2011

Micro hydraulic turbines take a growing interest because of its small and simple structure as well as high possibility of applying to micro and small hydropower resources. The differential pressure exiting within the city water pipelines can be used efficiently to generate electricity like the energy generated through gravitational potential energy in dams. In order to reduce water pressure at the inlet of water cleaning centers, pressure reducing valves are used widely. Therefore, pressure energy is wasted. Instead of using the pressure reduction valve, a micro counter-rotating hydraulic turbine can be replaced to get energy caused by the large differential pressure found in the city water pipelines. In this study, in order to acquire design data of counter-rotating tubular type micro-turbine, output power, head, and efficiency characteristics due to the diffuser.

• Proceedings of the KIEE Conference
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• 2000.07a
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• pp.175-181
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• 2000

월성원자력4호기가 '99.06.09일 11:53분 경 전출력 소외전원상실시험시 주발전기 병입차단기 및 기동용변압기 차단기의 트립과 동시에 예상 밖의 13.8Kv 원자로 냉각재펌프모터#3(9.000HP)이 순시과전류 보호계전기(50Y) 동작으로 트립되어 이로 인한 냉각재 저유량으로 원자로 제1정지계통이 동작되고 원자로가 비상정지 되어 동 시험이 실패되었음. 이 비정상적인 고장은 예비디젤발전기의 수동 기동 병입과 터빈 수동 정지 및 주발전기 트립후 적절한 조치로 소내전원은 정상적으로 복구되었음. 이에 대해 냉각재펌프모터#3의 순시과전류 동작 원인을 유도전동기의 전원상실 후 발생되는 잔류전압(Residual Voltage)과 공급 모선전압(Bus Voltage) 측면에서 분석하며, 모터의 회전속도, 위상각, 잔류전압크기 변화 및 신속개방 절체시 냉각재펌프모터의 돌입 기동전류를 계산하고, PSS/E 프로그램을 사용한 간략한 모의 사례로 검증하였으며 이에 대한 재발방지를 위한 대책을 제시함.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.05a
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• pp.107-110
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• 2008

The test range for turbopump and gas generator coupled test was determined considering the engine system test area which cover the qualification and development. Based on the test range, we determined the required loss coefficient for the throttle valves and lines.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.11a
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• pp.305-308
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• 2009

In this paper, we present the status and prospect for PAV propulsion system. Reciprocating engines are suitable for current PAV because of its efficiency and price advantages. However, fuel cells and batteries may replace conventional engines in the near future.

• Aerospace Engineering and Technology
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• v.3 no.2
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• pp.50-55
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• 2004

Performance predictions of the propulsion system were conducted for a 900㎏ class Canard Rotor/Wing vehicle. The main components of the propulsion system are turbojet engine, exhaust ducts and nozzles. The internal flow of the duct was considered as one-dimensional, compressible and viscous flow. Adequate governing equations including centrifugal force effect were applied to the analysis of the duct flows. Results such as available power, available thrust, engine throttle, mass flow rates, rotor RPM and cruise nozzle area were presented for rotary-wing mode and transition mode.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.26 no.11
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• pp.1605-1612
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• 2002

Thermodynamic performance analysis has been carried out for a hybrid electric power generation system combining a gas turbine and a solid oxide fuel cell and operating at over-atmospheric pressure. Performance characteristics with respect to main design parameters such as maximum temperature and pressure ratio are examined in detail. Effects of other important design parameters are investigated including fuel cell internal parameters such as fuel utilization factor, steam/carbon ratio and current density, and system parameters such as recuperator efficiency and compressor inlet temperature.

• Journal of the Korean Solar Energy Society
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• v.29 no.5
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• pp.73-80
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• 2009

A tidal current turbine is designed and analyzed numerically by using blade element momentum theory. The rated power has a limitation because the diameter of the tidal current turbine cannot exceed the depth of sea water. This study investigates a horizontal axis tidal-current turbine with a rated power of 500 kW. NACA-6 series laminar foil shape is used for basic airfoil along the blade span. The distributions of chord length and twist angle along the blade span are obtained from the hydrodynamic optimization procedure. Prandtl's tip loss correction and angle of attack correction considering the three-dimensional effect are applied for this study. The power coefficient curve shows maximum peak at the rated tip speed ratio of 6.0, and the maximum torque coefficient is developed at the tip speed ratio of 4. The drag coefficient reaches about 0.85 at the design tip speed ratio.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.33 no.5
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• pp.326-333
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• 2009

Design life-time of a wind turbine is required to be at least 20 years. In the meantime, the wind turbine will experience a lot of load cases such as extreme loads and fatigue loads which will include several typhoons per year and extreme gusts with 50 years recurrence period as well as endless turbulence flow. Therefore, IEC61400-1 specifies design load cases to be considered in the wind turbine design and requires the wind turbine to withstand the load cases in various operational situations. This paper investigates the ultimate loads which the wind turbine will experience for 20 years and their characteristics based on the IEC61400-1 using an aero-elastic software, GH-Bladed. And the performance characteristics of a wind turbine such as electrical power generation and annual energy yield are also investigated.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2012.06a
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• pp.154-154
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• 2012

Many suggestions is offered to resolve global warming. Tidal current generation is producing power by switched tidal difference sea water horizontal fluid flow produced by tidal difference using rotor and generator. So, change the angle of inflow condition due to the entrance of efficiency are considered. We therefore investigated three dimensional flow analysis and performance evaluation using commercial ANSYS-CFX code for horizontal axis turbine. Then We also studied three dimensional flow characteristics of a rotating rotor and blade surface streamlines around a rotor. As a result, Cp was highest at TSR 5.5, especially the larger changes in the angle of inflow condition decreased efficiency.

• Journal of the korean Society of Automotive Engineers
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• v.6 no.4
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• pp.12-17
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• 1984

인류문명의 발달과 더불어 자동차는 우리의 일상생활에서 가장 긴요한 문명의 이기로서 교통 및 수송수단의 대부분을 차지하고 있음은 주지의 사실이다. 좀더 편리하고 이상적인 자동차를 지 향하려는 인간의 의지는 자동차의 기관을 비롯하여 각종장치의 구조 및 작동성능을 최적화하는데 크게 이바지하여 왔으며, 이러한 노력은 자동차용 기관의 효율증대와 배기저감 등에 많은 발 전을 가져오게 되었다. 특히 에너지타동이후 우리나라를 비롯한 세계여러나라는 자원의 소비절 약을 극대화하려는 방향으로 많은 연구가 이루어지고 있다. 자동차용 연소기관의 성능은 초기 에는 주로 출력성능에 주안을 두어 설계하여 왔으나 점차 배기에 의한 대기오염문제가 제기됨에 따라 배기가스의 유해성분저감, 소음저감, 내구성 증대를 비롯하여 연료소비절감을 감안한 경 제성을 감안하여 설계하게 되었으며 최근에는 이들을 충족시키면서도 최적제어시스템을 갖는 자동차로 발전하게 되었다. 자동차용 연소기관의 주류는 지금까지 사용하여 오고 있는 가솔린 기관, 디이젤기관이며 이 외에도 가스 터빈, 전기자동차용기관, 등이 일부 사용되고 있다. 이 러한 관점에서 여기서는 주로 자동차용 가솔린기관과 디이젤기관의 진전과 최근의 동향에 대하여 개괄적으로 고찰하여 보기로 한다.