• 한국기계가공학회지
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• 제11권5호
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• pp.104-108
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• 2012

Recently, small scale hydropower needs to be developed due to its clean, renewable and abundant energy resources. However, suitable draft of hydro-turbine body in combination with differences in wheel blade shapes is not determined yet in the range of small hydropower and it is necessary to study for the effective draft in combination with type. Therefore, watermill shaped of 250mm diameter. hydro-turbine aiming 20 watt class generator is adopted in this study because of its simple structure and high possibility of applying to small hydropower. The result shows that effective draft for the turbine body is variable concerning the size of turbine and flow rate of water. Thus, the difference of water depth between fore and aft turbine body contributes to the increase of torque, angular momentum and power output.

• 설비공학논문집
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• 제21권8호
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• pp.448-455
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• 2009

A performance analysis of the regenerative gas turbine system with afterfogging is carried out. Because of the high temperature at the outlet of air compressor, afterfogging has a potential of improved recuperation of exhaust heat than inlet fogging. Thermodynamic analysis model of the gas turbine system is developed by using an ideal gas assumption. Using the model, the effects of pressure ratio, water injection ratio, and ambient temperature are investigated parametrically on thermal efficiency and specific power of the cycle. The dependency of pressure ratio giving peak thermal efficiency is also investigated. The results of numerical computation for the typical cases show that the regenerative gas turbine system with afterfogging can make a notable enhancement of thermal efficiency and specific power. In addition, the peak thermal efficiency is shown to decrease almost linearly with ambient temperature.

• 한국수소및신에너지학회논문집
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• 제31권3호
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• pp.328-336
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• 2020

In the Francis turbine, the leakage flow through the runner gaps which are between the runner and the stator structure influences the internal flow and hydraulic performance. Thus, the investigation for the flow characteristics induced by the runner gaps is important. However, the runner gaps are often disregarded by considering the time and cost of the numerical analysis. Therefore, in this study, the flow characteristics according to runner gaps of the Francis turbine model were investigated including the leakage flow of the runner cone. The three-dimensional unsteady Reynolds-averaged Navier-Stokes analyses were conducted using a scale-adaptive simulation shear stress transport as a turbulence model for observing the influence of the leakage flow on the internal flow and hydraulic performance. The efficiencies were decreased slightly with runner gaps; and the complicated flows were captured in the gaps.

• 에너지공학
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• 제23권4호
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• pp.263-271
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• 2014

터빈 사이클의 성능 상태량을 결정하기 위한 보정 열 성능 분석은 발전소의 향상된 경제성 운전을 위해 요구된다. 본 연구에서는 유용하고 정확한 성능 분석을 위해서 산업 표준인 ASME PTC를 기분으로 하여 성능 데이터를 사용하여 주급수 유량의 영역별 판정 알고리듬을 개발하고 각 영역별 추정 알고리즘을 개발하였다. 추정 알고리즘은 측정 상태량의 상관관계를 기반으로 형상 분류를 제시하고, 이를 기반으로 서포트 벡터 머신 모델링을 이용하여 추정 모델을 구성하였으며, 서포트 벡터 머신 모델링의 우수성을 검증하기 위하여 신경 회로망 모델, 커널 회귀 모델과 비교하였다. 주급수 유량의 형상 분류 및 추정 모델은 터빈 사이클에서 정확한 보정 열 성능 분석을 제공함으로써 향상된 성능 분석에 기여할 것이다.

• 사물인터넷융복합논문지
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• 제8권1호
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• pp.23-29
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• 2022

본 연구의 개발대상 제품은 선박 및 발전용 EGB(Exhaust Gas Boiler-폐열보일러) 종류로써 디젤 엔진, 가스 엔진, 가스 터빈 등에서 나오는 배기 가스의 여열을 이용하여 물을 가열하여 고온·고압의 증기나 온수를 발생시키는 열회수 장치이다. 발생된 증기나 온수는 선박의 선실 난방 및 온수 시설이나 HFO Heating, 터빈 구동에 필요한 동력원으로 사용된다. 폐열보일러의 원리는 여열을 가진 고온의 배기 가스가 보일러의 Tube를 통과하면서 물을 데우는 역할을 한다. 데워진 물은 스팀 형태로 선실이나 터빈장치로 보내어져 사용하게 되는 구조이다. 본 연구에서는 EGB의 열전달 부품인 관형 튜브를 Plate Tube로 대체하여 열전달 표면을 늘려 효율을 극대화하는데 목표가 있다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 춘계학술대회논문집
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• pp.46-50
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• 2007

The nuclear power plant's turbine-generator system had been suffered form some problems, such as high shaft vibration, generator casing crack, stator coil water leakage, high $H_2$ gas consumption rate. Those kinds of problems were related to high vibration. So nuclear plant decided to replace generator in order to reduce rotor high vibration and high thermal sensitivity. A series of effort to reduce turbine-generator vibration was carried out as followings, first of all, replacement of generator, analysis of turbine-generator vibration, LP B rotor shop balancing, improvement of LP B/Gen coupling run-out, improvement of Generator basement and field balancing. Finally the nuclear turbine-generator's shaft vibration was reduced below $60{\mu}m$ from over $200{\mu}m$ which is very excellent vibration in nuclear turbine-generator in Korea.

• International Journal of Fluid Machinery and Systems
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• 제1권1호
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• pp.148-154
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• 2008

The Wells turbine rotor consists of several symmetric airfoil blades arranged around a central hub, and the stagger angle is 90 degrees. These characteristics simplify the total construction of OWC type wave energy converters. Although the Wells turbine is simple, the turbine produces a complicated flow field due to the peculiar arrangement of blades, which can rotate in the same direction irrespective of the oscillating airflow. In order to understand these flows, flow visualization is carried out with an oil-film method in the water tunnel. This research aims to analyze the mechanism of the 3-D flows around the turbine with the flow visualization. The flow visualization explained the influence of attack angle, the difference between fan-shaped and rectangular wings, and the sweep angle.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2007년도 추계학술대회 논문집
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• pp.408-411
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• 2007

The small hydropower uses hydraulic power to generate electricity, which one of the future energy resources of the power industry. The tubular turbine which uses in the city water pipe lines's differential pressure electricity is produced, this structure is simple, and therefore advantageous. The effects of cavitation that occurs in the turbine is researched, By using CFD we analysed the flow pattern inside the turbine. As a result, we found out to become the performance fall of turbine.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2004년도 학술대회지
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• pp.220-224
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• 2004

The present paper deals with the numerical study to analyze the self-starting performance of impulse turbine in a reciprocating air flow generated by sinusoidal motion of wave inside oscillating water column. Result was compared to that of Wells turbine, well-known wave energy conversion device, and showed that the impulse turbine has a superior self-starting ability. More detailed parametric study was performed to demonstrate the effects of moment of inertia of rotor, loading torque, tip clearance and angle of guide vane.

• 대한기계학회논문집B
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• 제24권7호
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• pp.994-1001
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• 2000

The dynamic behavior of a single-pressure heat recovery steam generator and turbine system for the combined cycle power plant is simulated on the basis of one-dimensional unsteady governing equations. A water level control and a turbine power control are also included in the calculation routine. Transient response of the system to the variation of gas turbine exit condition is simulated and effect of the turbine power control on the system response is examined. In addition, the effect of the treatment of inertia terms(fluid inertia and thermal inertia of heat exchanger metal) on the simulated transient response is investigated.