• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.1033-1038
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• 2003

A wind turbine obtains its power input by converting the force of the wind into a torque (turning force) acting on the rotor blades. The amount of energy which the wind transfers to the rotor depends on the density of the air, the rotor area, and the wind speed. Because it has long term operating life and very complex load condition, the fatigue strength of each component must be considered. In this paper, we calculated the load condition by wind using a combined blade elemental theory and a FEM based analytical approach was use to evaluate the fatigue strength of a Hub of wind turbine. The effect of tensile mean stress was taken into account by the modified Goodman diagram. Using this approaches, we evaluated the fatigue strength of hub and main shaft and improved the design.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2005년도 전력전자학술대회 논문집
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• pp.411-413
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• 2005

This paper proposes a modeling of wind turbine simulator which includes the dynamic characteristics such as pitch angle control, torsional vibration, and tower effect. Simulation results using PSCAD are provided to show the wind turbine simulator performance.

• 한국유체기계학회 논문집
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• 제19권1호
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• pp.24-30
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• 2016

In this study, a 2W micro-gas turbine engine was designed using micro-electro-mechanical systems (MEMS) technology, and experimental investigations of its potential under actual combustion conditions were performed. A micro-gas turbine (MGT) contains a turbo-charger, combustor, and generator. Compressor and turbine blades, and generator coil were manufactured using MEMS technology. The shaft was supported by a precision computer numerical control (CNC) machined static air bearing, and a permanent magnet was attached to the end of the shaft for generation. A heat transfer analysis found that the cooling effect of the air bearing and compressor was sufficient to cover the combustor's high temperature, which was verified in an actual experiment. The generator performance test showed that it can generate 2W at design rotational speed. Prototype micro-gas turbine generated maximum 1 mW electric power and lasted up to 15 minutes.

• 한국유체기계학회 논문집
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• 제14권6호
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• pp.91-95
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• 2011

This paper deals with the detail rotordynamic analysis for the assembly rotor composed of turbine wheel, turbine shaft, connecting arbor, and flange & spindle in order to perform the spin test of turbocharger turbine. Prior to rotordynamic analysis, the 1st spin test was performed but the test was failed by excess vibration in the neighborhood rated speed. It is the reason for this fail that the separation margin between the rated speed and critical speed is not enough, confirmed by rotordynamic analysis results. Since then, the dimension of turbine shaft was modified and the critical speeds were again reviewed for modified assmebly rotor. In results, the separation margin between the rated speed and critical speed is over 20% and then the 2nd spin test was performed successfully. In preparing spin test for turbine, compressor wheels and etc., the geometry design of connecting arbor and dimension of rough machining should be reviewed by considering rotordynamic results, and the separation margin should be enough for successful spin test.

• 한국추진공학회지
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• 제8권3호
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• pp.17-26
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• 2004

본 연구에서 동력 전달 시스템은 분리 축 방식의 가스 터빈 엔진의 축 동력을 발전기 전력으로 변환하여, 이것을 프로펠러를 구동하는 추력 모터에 공급하는 방식으로 구성되어있다. 여기에 사용된 가스 터빈 엔진은 엔진 축 마력 317shp(236kw)을 약110kw (147shp)으로 플랫 레이팅(flat rating) 하여 운용한다. 본 시험 장치의 엔진은 가스 터빈엔진 출력축과 발전기 사이에 부하 변화 시 댐핑(damping)역할을 할 수 있도록 플라이 휠(flywheel)을 장착하였다. 이 때 플라이휠의 적절한 관성 모멘트가 고려되지 않으면, 발전기와 모터는 부하 상승에 의한 엔진으로부터 요구되는 출력을 얻을 수 없으며, 또한 엔진이 정상적으로 작동하지 않음을 확인할 수 있다. 따라서 제공된 엔진 데이터와 엔진 시험 데이터로부터 동역학적인 천이 효과에 의한 성능 분석을 함으로써 관성 모멘트의 요구 범위를 결정하였다. 재설계한 플라이휠을 장착 시험한 결과, 본 시스템에서 요구한 출력을 얻을 수 있었다.

• 대한기계학회논문집A
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• 제38권4호
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• pp.437-442
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• 2014

원자력 발전소의 터빈-발전기 시스템과 같이 일정한 토크와 함께 축 진동에 의한 가변 응력이 인가되는 부재의 경우 비틀림 응력에 의한 피로 파괴 거동을 보인다. 따라서 본 연구에서는 터빈-발전기의 터빈 축에 인가하는 비틀림 응력을 측정하고 응력에 의해 발생하는 피로 파괴 거동을 분석하는 것을 목적으로 하였다. 이를 위해 터빈-발전기 시스템과 같은 실험 장치를 제작하고 임의의 부하를 인가하여 다양한 비틀림 응력에 대한 피로 파괴 거동을 평가하였다. 특히 기존의 알려진 피로 거동 평가 방법인 응력-수명, 변형률-수명, 균열성장 평가 방법을 동시에 적용하여 평가를 진행하였다. 부하의 크기가 증가하면서 평가 방법과 무관하게 피로 수명이 감소하는 경향이 확인하였으며 5 kV 부하 인가 시 최대 10배의 피로 수명의 감소가 발생하였다.

• 한국해양공학회지
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• 제28권4호
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• pp.314-323
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• 2014

In this study, a gearbox and blade were modeled in the MASTA program, and the housing and carrier components were modeled using a finite element method. Using substructure synthesis, all the components were combined and used to establish a vibration model of a 2.5-MW wind turbine gearbox. In addition, the safety displacement factor was evaluated using an AGMA data sheet about bearing's outer race for the input shaft and output shaft. As a result, the bearing's outer race for the input shaft, and the radial and axial responses were satisfied by the $1^{st}$ and $2^{nd}$ planetary gears and the $3^{nd}$ helical gear transmission error(TE), respectively. However, the output shaft support bearing's outer race responses were not satisfied with the radial response by the $2^{nd}$ TE and axial response by the $3^{rd}$ TE. To reduce the vibration, tooth modification was needed. After profile tooth modification, at the outer race of the output shaft support bearing, the radial response was reduced by approximately $20{\mu}m$, and the axial response was reduced by approximately $6{\mu}m$.

• 소음진동
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• 제8권5호
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• pp.922-928
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• 1998

This paper presents the automatic alignment measuring system for improving the accuracy and working time of alignment of large vertical hydraulic pump turbine. It is general practice that rotating shaft should run within acceptable vibration limit. In order to obtain better run-out data of multi-stage rotor, careful and accurate alignment approach must be established. Generally, present alignment procedure are required several iterative works and so many manpower. Therefore, the new system has been developed using a vector calculation algorithm, laser sensor and data acquisition devices. As a result of appling to actual machines, it is confirmed that manpower is saved up to an average 90%.

• 플랜트 저널
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• 제13권1호
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• pp.30-36
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• 2017

본 연구에서는 500 MW급 석탄화력발전소 기동 중 고압 및 중압 증기터빈축 양단 베어링에서 발생한 이상진동 현상의 원인을 규명하고 해결방안을 모색하기 위하여 알려진 이론에 근거하여 분석을 수행하였다. 주파수, 진폭 및 위상각 분석결과 접촉에 의해 발생하는 진동의 전형적인 특성이 나타나 이상진동의 원인을 접촉으로 판단하였고 증기터빈을 분해하여 내부부품의 마모를 확인하였다. 이상진동을 해소하기 위하여 저속회전 및 발란싱 방법을 적용하였는데 발란싱이 저속회전보다 접촉현상 해소에 우수하였다. 따라서 본 연구와 유사한 특성의 이상진동이 증기터빈 축에서 발생할 경우 발란싱은 유력한 해결방안이 될 수 있을 것이다.

• 한국소음진동공학회논문집
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• 제12권5호
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• pp.380-388
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• 2002

This paper describes the optimum design for low-pressure steam turbine rotor of 1,000 MW nuclear power plant by using a combined genetic algorithm, which uses both a genetic algorithm and a local concentrate search algorithm (e.g. simplex method). This algorithm is not only faster than the standard genetic algorithm but also supplies a more accurate solution. In addition, this algorithm can find the global and local optimum solutions. The objective is to minimize the resonance response (Q factor) and total weight of the shaft, and to separate the critical speeds as far from the operating speed as possible. These factors play very important roles in designing a rotor-bearing system under the dynamic behavior constraint. In the present work, the shaft diameter, the bearing length, and clearance are used as the design variables. The results show that the proposed algorithm can improve the Q factor and reduce the weight of the shaft and the 1st critical speed.