• International Journal of Fluid Machinery and Systems
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• 제9권4호
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• pp.300-306
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• 2016

A twin unidirectional impulse turbine for wave energy conversion has been suggested in our previous study, and the performance under unsteady flow has been investigated by quasi-steady analysis. In the present study, the performance of twin impulse turbine under unsteady flow condition has been investigated by unsteady analysis of Computational fluid dynamics. As a result, the mean efficiency of twin unidirectional impulse turbine under unsteady flow is lower than the maximum efficiency of unidirectional impulse turbine. Moreover, it is verified that airflow goes backward in the reverse turbine in low flow rates.

• International Journal of Aerospace System Engineering
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• 제3권1호
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• pp.25-29
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• 2016

This paper highlights the performance of an impulse turbine which is a part of turbopump in a liquid rocket first stage engine. The turbopump, currently under development at Korea Aerospace Research Institute, has an impulse type turbine with 12 nozzles and a single rotor. The impulse turbine can archive high specific power with the low gas flow rates. The supersonic impulse turbine with a single rotor can make a simple structure. High-pressure gases are converted into the dynamic energy with flows through the 12 nozzles and drive the rotor to make the power for the pumps. The turbine test was performed in the high-pressured turbine test facility with air gas instead of burned gas. A hydraulic dynamometer was used to absorb the power from the turbine and control the rotational speed and torque. The test points were at several pressure ratios with 7 different rotational speeds. Results showed the efficiency was highest at the design pressure ratio. The efficiency was insensitive to the pressure ratio variation than the rotational speed. It was a typical characteristic in an impulse turbine.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2003년도 유체기계 연구개발 발표회 논문집
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• pp.3-12
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• 2003

This paper reviews the present state of the art on the self-rectifying air turbines, which could be used for wave energy conversion. The overall performances of the turbines under irregular wave conditions, which typically occur in the sea, have been evaluated numerically and compared from the viewpoints of the starting and running characteristics. The types of turbine included in the paper are as follows: (a) Wells turbine with guide vanes (WTGV); (b) turbine with self-pitch-controlled blades (TSCB); (c) biplane Wells turbine with guide vanes (BWGV); (d) impulse turbine with self-pitch-controlled guide vanes (ISGV) and (e) impulse turbine with fixed guide vanes (IFGV). As a result, under irregular wave conditions it is found that the running and starting characteristics of the impulse type turbines could be superior to those of the Wells turbine. Moreover, the authors have explained the mechanism of hysteretic behavior of the Wells turbine and the necessity of links for improvement of the performance of ISGV.

• Journal of Advanced Marine Engineering and Technology
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• 제30권2호
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• pp.284-290
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• 2006

For the case of high head and critical low flow rate range of micro hydropower resources, it requires very low specific speed turbines which are lower than conventional impulse turbine's specific speed. In order to satisfy the request for very low specific speed turbine with high efficiency, a new positive displacement turbine is developed. The performance characteristics of the new turbine is tested and compared with a conventional impulse turbine, which is used for automatic water faucet system. The purpose of present study is to develop an high performance turbine that can be used to extract micro hydropower potential of a water supply system. The test results show that the positive displacement turbine is much more efficient than the conventional turbine and it can sustain high efficiency under the wide range of operating conditions. The pressure pulsations at the inlet and outlet of the positive displacement turbine can be considerably minimized by using simple pressure damper.

• 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.

• Journal of Advanced Marine Engineering and Technology
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• 제27권4호
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• pp.535-541
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• 2003

This paper describes numerical analysis of the impulse turbine with fixed guide vanes, a high performance hi-directional air turbine having simple structure for wane energy conversion. A 3-dimensional incompressible viscous flow numerical analysis based on the full Reynolds-averaged Wavier-Stokes equations was made to investigate the internal flow behavior Numerical results ate compared with experimental data. As a result, a suitable choice for the one of design factors has been clarified.

• 항공우주기술
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• 제6권2호
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• pp.197-204
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• 2007

터번로터 팁 형상의 변화에 따른 터보펌프 터빈의 성능변화에 대하여 실험적 연구를 수행하였다. 한국항공우주연구원에서 개발중인 30톤급 터보펌프용에 장착된 초음속 충동형 터빈을 기본 모델로 하여 터번로터 슈라우드 유무 및 팁간극 크기에 따른 터빈성능변화를 측정 비교하였으며, 이와 더불어 노즐-로터 오버랩에 따른 터빈성능 변화 연구도 함께 이루어졌다. 시험 수행 결과, 로터 슈라우드 유무에 따라 터빈성능의 절대량은 크게 변화하나 팁간극의 변화에 따른 터빈효율의 민감도는 초음속 충동형 터빈의 경우 고효율 아음속터빈에 비해 크게 작은 것으로 나타났다. 아울러, 최적 효율을 나타내는 노즐-로터 오버랩 값이 존재하는 것을 실험을 통해 확인하였다.

• 한국추진공학회지
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• 제11권4호
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• pp.59-66
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• 2007

부분분사비에 따른 초음속 충동형 터빈 성능변화에 대하여 실험적 연구를 수행하였다. 실험은 개방형액체로켓 엔진의 터보펌프에 사용되는 터빈을 이용하였으며 부분분사비 조절을 위해 실험용 노즐블럭을 설계/제작하였다. 실험에 사용된 터빈은 축대칭 수축-확산형 노즐을 갖고 있으며 작동노즐의 개수조절을 통해 부분분사비를 변화시켰다. 작동유체는 고압공기를 사용하였다. 실험결과 초음속 충동형 축류터빈은 부분분사비 변화에 따른 성능변화가 크지 않은 것으로 나타났다.

• 한국유체기계학회 논문집
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• 제8권6호
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• pp.26-32
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• 2005

1.6 MW class supersonic partial admission impulse turbine has been designed and tested in Korea Aerospace Research Institute for the liquid rocket engine application. The test has been performed using a high pressure air source facility in KARI. For the turbine power absorption, a hydraulic dynamometer has been used. Appropriate similarity relations are used for the determination of test condition. Various settings of turbine pressure ratio and rotational speed are tested to investigate global turbine characteristics. From measured data, parameters related to the turbine design are derived and validated.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2004년도 유체기계 연구개발 발표회 논문집
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• pp.125-131
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• 2004

1.6 MW class supersonic partial admission impulse turbine has been designed and tested in Korea Aerospace Research Institute for the liquid rocket engine application. The test has been performed using a high pressure air source facility in KARI. For the turbine power absorption, a hydraulic dynamometer is used. Appropriate similarity relations are used for the determination of test condition. Various settings of turbine pressure ratio and rotational speed are tested to investigate global turbine characteristics. From measured data, Parameters related to the turbine design are derived and validated.