• 한국분무공학회지
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• 제24권3호
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• pp.130-136
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• 2019

Spray visualization of a vaporizer fuel injection system of a micro turbo jet engine was experimentally studied. The fuel heating by combustion was simulated by the high pressure steam generator and combustor inlet air from the centrifugal compressor was simulated by compressed air stored in the high pressure air tank. Spray visualization was performed with single vaporizer, and then six vaporizers which are same number of micro turbojet engine were used. As a results, the spray characteristics of the vaporizer were understood with pressure difference of the combustor inlet air and the fuel supply pressure. Spray angles with three types of vaporizer configuration were measured. In the results, guide vane configuration has a wider spray angle than the straight tube and smooth curve tube with a swirler, so it is expected that the fuel will be effectively distributed inside the combustor flame tube.

• 조명전기설비학회논문지
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• 제23권10호
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• pp.52-58
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• 2009

본 논문에서는 마이크로그리드(Micro grid, MG)의 설계에서 필요로 되는 에너지저장장치(Energy storage system, ESS)의 최소설비용량을 산정할 수 있는 확률론적 방법론을 제시하였다. ESS기술은 아직까지 경제성 측면에서 매우 높은 설비비용이 필요로 되기 때문에 적정 설비규모를 산정하는 것과 MG의 안정적인 운영을 위해서 최소 설비용량에 대한 가이드라인의 제시가 필요로 된다. 본 논문에서 제시한 방법론은 Non-dispatchable 발전원 출력의 간헐성과 모든 발전기의 고장정지확률을 고려하여 MG가 자체적인 에너지 Self balancing을 유지할 수 있는 ESS의 최소설비용량을 산정할 수 있는 것을 특징으로 한다.

• 대한토목학회논문집
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• 제32권6A호
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• pp.369-378
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• 2012

이 연구에서는 풍력 터빈 블레이드의 형상 최적화를 위한 직접탐색 기반의 최적화 기법을 적용하고, 최적화 기법간의 성능을 비교하여 효과적인 방법을 제안하고자 하였다. 이를 위하여 수평축 풍력 터빈의 최적설계 코드인 HARP_Opt(Horizontal Axis Rotor Performance Optimizer)을 기반으로 연간 발전량 평가 방법을 수정하고, HARP_Opt에서 적용하고 있는 기존의 유전자 알고리즘과 함께 패턴 서치 방법을 추가 적용하였다. 이를 1MW급 풍력 발전 터빈 블레이드의 단면 형상 최적 설계 문제에 적용하였으며, 기존의 유전자 알고리즘 및 마이크로 유전자 알고리즘, 그리고 패턴 서치 방법의 성능을 비교한 결과, 연간 발전량과 해의 일관성 면에 있어서는 패턴 서치 방법이 상대적으로 우수하였으며, 계산시간 측면에서는 마이크로 유전자 알고리즘이 상대적으로 우수한 것으로 분석되었다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.2839-2844
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• 2007

Micro hydraulic power generation of which the output is less or equal to a 100kW is attracting considerable attention. This is because of its small, simple, renewable, and abundant energy resources. By using a small hydropower generator of which main concept is based on using the different water pressure levels in pipe lines, energy which was initially wasted by use of a reducing valve at the end of the pipeline, is collected by turbine in the hydropower generator. A propeller shaped hydroturbine has been used in order to use this renewable pressure energy. In this study, in order to acquire basic design data of tubular type hydraulic turbine, output power, head, efficiency characteristics due to the flow coefficient are examined in detail. Moreover influences of pressure and velocity distributions with the variations of runner vane angle on turbine performance are investigated by using a commercial CFD code.

• 대한기계학회논문집B
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• 제34권9호
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• pp.835-841
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• 2010

MEMS 가스터빈 엔진에서 연료와 공기의 혼합에 영향을 미치는 중요한 요소중 하나는 연료 분사구 형상의 설계이다. 본 연구에서는 3 개의 연료 주입부와 각 주입부에 연결된 여러 개의 분사구에 의해 연료와 공기가 혼합되는 시스템을 고려하여 분사구의 배열과 연료 공급비율의 변화에 따른 혼합 정도를 당량비를 통하여 정량적으로 해석하였다.

• 한국지능시스템학회논문지
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• 제26권5호
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• pp.351-360
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• 2016

Rapid population growth with high living standards and high electronics use for personal comfort has raised the electricity demand exponentially. To fulfill this elevated demand, conventional energy sources are shifting towards low production cost and long term usable alternative energy sources. Hybrid renewable energy systems (HRES) are becoming popular as stand-alone power systems for providing electricity in remote areas due to advancement in renewable energy technologies and subsequent rise in prices of petroleum products. Wind and solar power are considered feasible replacement to fossil fuels as the prediction of the fuel shortage in the near future, forced all operators involved in energy production to explore this new and clean source of power. Presented paper proposes fuzzy logic based Energy Management System (EMS) for Wind Turbine (WT), Photo Voltaic (PV) and Diesel Generator (DG) hybrid micro-grid configuration. Battery backup system is introduced for worst environmental conditions or high load demands. Dump load along with dump load controller is implemented for over voltage and over speed protection. Fuzzy logic based supervisory control system performs the power flow control between different scenarios such as battery charging, battery backup, dump load activation and DG backup in most intellectual way.

• 한국추진공학회지
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• 제13권6호
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• pp.1-7
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• 2009

가스터빈 엔진의 성능은 그 구성품 성능 특성에 큰 영향을 받는다. 보통 이러한 구성품 성능 특성은 여러 조건에서의 수많은 실험을 통해 얻을 수 있지만 그것은 제작사의 고유 재산이기 때문에 쉽게 제공되지 않는다. 그렇기 때문에 보통 성능 덱을 이용하거나 소유하고 있는 엔진 성능 맵을 스케일링 하여 사용한다. 하지만 이러한 방법은 탈설계점에서 오차를 보인다. 이에 본 연구에서는 소형 가스터빈 엔진 실험 장치를 구성하여 몇 구간에서의 실험을 통해 데이터를 축적하고 이를 이용하여 구성품 성능 맵을 축척하는 방법을 제시하였다. 그리고 프로그램을 이용하여 대상 엔진의 정상상태 성능 모델을 구성하여 실제 측정 데이터와 새롭게 생성된 구성품 맵을 사용했을 경우, 그리고 기존의 방법을 이용한 경우를 비교하였다.

• 한국초전도ㆍ저온공학회논문지
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• 제12권2호
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• pp.17-20
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• 2010

A considerable amount of research material discussing designs and properties of High Temperature Superconducting Fault Current Limiter (HTS FCL) is available. However, a shortage of research concerning positioning of HTS FCL in power grid is felt. In this paper a feasibility study of HTS FCL positioning in Smart Grid through simulation analysis is carried out. A complete power network (including generation, transmission and distribution) is modeled in Simulink / SimPowerSystems. A generalized HTS FCL is also designed by integrating Simulink and SimPowerSystem blocks. The distribution network of the model has a wind turbine attached to it forming a micro grid. Three phase fault have been simulated along with placing FCL models at key points of the distribution grid. It is observed that distribution grid, having distributed generation sources attached to it, must not have a single FCL located at the substation level. Optimized HTS FCL location regarding the best fault current contribution from wind turbine has been determined through simulation analysis.

• 한국생산제조학회지
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• 제19권3호
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• pp.334-339
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• 2010

The development of high-speed spindle have been studied extensively for micro machining in advanced industrial countries. The research of miniaturized high-speed air spindle is important part which needs for the micro machining process of high quality. So, This study was to carry out results about design characteristics of miniaturized high-speed air spindle. We had designed 4type turbines and shaft. They were simulated in use the computer simulation programs. We made them as products. They measured RPM (revolutions per minute). As a result of experiments, there was a contrast among 4type Turbines. it reached 384,000rpm in 4.5bar of air pressure. And, We tried to compare the results of measurement whit the results of computer simulation.

• Journal of Electrical Engineering and Technology
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• 제13권1호
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• pp.30-37
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• 2018

Unlike an AC system, a DC system does not cause problems with synchronization, stability, reactive power, system losses, and cost. However, more research is still required for the application of DC Systems. This paper proposes a stable black-start strategy for a stand-alone DC micro-grid, which consists of an energy storage system, photovoltaic generator, wind-turbine generator, diesel generator, and DC loads. The proposed method is very important for avoiding inrush current and transient overvoltage in the power system equipment during restoration after a blackout. PSCAD/EMTDC software was used to simulate, analyze, and verify the method, which was found to be stable and applicable for a stand-alone DC micro-grid.