• 대한기계학회논문집B
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• 제33권12호
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• pp.933-938
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• 2009

Hot test of a full-scale turbopump for a 30-ton-thrust liquid rocket engine was carried out. The turbopump is composed of an oxidizer pump, a fuel pump, and a turbine on a single shaft. Model fluid was used in the test, that is, hot air for the turbine and water for the pumps. The turbopump was operated stably at full speed for 120 seconds. In terms of performance characteristics of pumps and turbine, the results from the turbopump assembly test are compared with those from the turbopump component tests which were performed at about half of the design rotational speed.

• International Journal of Fluid Machinery and Systems
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• 제2권4호
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• pp.418-425
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• 2009

A vertical bulb turbine unit with elbow type draft tube has been developed due to avoidance of complicated assembling and long standstill period at overhaul in comparison with conventional horizontal bulb turbine unit. Before designing the prototype vertical bulb unit, a hydrographic model test was carried out to establish the ideal design concept for this innovative generating unit. Froude similarity is not available for vortex occurrence. Consequently, an intake structure without air entraining vortices under all the flow conditions is developed, and it is confirmed that the surge wave at load rejection is not affected harmful influence for other constructions.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2009년도 추계학술대회 논문집
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• pp.606-609
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• 2009

Development of renewable energy is very important because of environmental problems caused by greenhouse effect. This is due to the use of fossil fuels which has serious consequences. Therefore, development of small hydropower can be a good countermeasure for the problems. The small hydropower is clean energy because the small hydropower generates few $CO_2$. Moreover, as the energy density by the small hydropower is high, it is economical for a society which wants to introduce the system. The purpose of this study is to improve the turbine performance. This study is about tubular-type hydro turbine among renewable energy that is based using the different water pressure level in pipe lines. The analysis was performed using the commercial CFD code ANSYS-CFX.

• 항공우주시스템공학회지
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• 제7권4호
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• pp.49-54
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• 2013

A turbopump for a 75 ton class liquid rocket engine was tested at full speed for 20 seconds using model fluid. Liquid nitrogen is used for the oxidizer pump, water for the fuel pump, and hot gas for the turbine. The non-cavitating head of pump from the turbopump assembly test showed a good agreement with that from the pump component test. The relative difference of turbine efficiency between the turbopump assembly test and the turbine component test was 0.3% only. Suction performance from the turbopump assembly test was higher than that of pump component test, which resulted from the thermodynamic effect of cavitation.

• 동력기계공학회지
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• 제10권4호
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• pp.105-110
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• 2006

Among many other alternative energy resources, small scale hydro power has been brought into attention as a reliable source of energy today, which had been relatively neglected since 1960s. Especially, Kaplan micro-turbine can be applied to various kind of small hydro power plants, such as reservoirs for agriculture purpose, sewage treatment plants and water purification plants. However present low head of Kaplan micro-turbines and small scale hydro turbines, have limitations in the minimum required head and flow rate for efficient operation. This research is to develop modeling analysis for the Kaplan micro-turbine, which can improve economical features of small hydro power plants. The contents and scope of this research are the efficiency improvement of Kaplan micro-turbine.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 추계 학술발표회
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• pp.825-839
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• 2010

The global and domestic market for offshore wind farm is expected to grow fast, and the design and installation of substructure and foundation is getting more important. As for the offshore wind farms located in the shallow(depth < 20m) water, the construction and installation of the substructure and foundation makes up about 1/4 ~1/3 of the offshore wind farm construction cost, and the portion is expected to increase because the turbine capacity is increasing from 2 ~ 3MW to 5MW or larger and the water depth of wind farms is also increasing over 30m. As a foundation for offshore wind turbine, the suction caisson foundation is being considered to be a highly competitive alternative to the conventional monopile or gravity based structure, because it has features suitable for the offshore construction such as quick installation, no heavy equipment for penetration and no hammering noise for driving. In order to study the installation behaviour of the suction caisson, laboratory tests were performed with sand. The pore water pressure and displacement were measured to analyze the suction pressure during penetration, the penetration speed and the amount of heaving.

• 한국해양환경ㆍ에너지학회지
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• 제15권2호
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• pp.111-117
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• 2012

진동수주형 파력발전장치는 가장 널리 사용되는 파력에너지 변환장치이다. 시스템의 작동성능은 1차 변환장치인 공기실 성능과 2차 변환장치인 터빈의 성능에 지배적인 영향을 받는다고 볼 수 있다. 본 연구에서는 터빈의 영향을 시스템에 적용하기 위하여 오리피스 모델을 채택하여 성능을 검증하였고 공기실 성능예측을 위하여 VOF 기반의 수치조파수조가 사용되었다. 터빈의 영향을 고려했을 때, 공기실 내부에서 일어나는 공기와 물의 복잡한 상호작용을 수치적인 방법을 이용하여 예측하였다. 입사파 조건 및 다양한 공기실 형상이 시스템 성능에 미치는 영향에 대하여 고찰하였고, 터빈의 영향을 고려한 공기실 내의 수면, 압력, 유량의 변화를 실험적 및 수치적으로 고찰하여 비교분석을 수행하였다.

• International Journal of Fluid Machinery and Systems
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• 제10권3호
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• pp.287-295
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• 2017

The most detrimental pressure pulsations in high-head pump-turbines is caused by the rotor-stator interaction (RSI) between the guide vanes and runner blades. When the pump-turbine operates in the S-shaped region of the characteristic curves, the deteriorative flow structures may significantly strengthen RSI, causing larger pressure pulsations and stronger vibration with an increased risk of mechanical failure. CFD simulations were carried out to analyze the impacts of flow evolution on the pressure pulsations in the S-shaped region of a model pump-turbine. The results show that the reverse flow vortex structures (RFVS) at the runner inlet have regular development and transition patterns when discharge reduces from the best efficiency point (BEP). The RFVS first occur at the hub side, and then shift to the mid-span near the no-load point, which cause the strongest pressure pulsations. The locally distributed RFVS at hub side enhance the local RSI and makes the pressure fluctuations at the corresponding sections stronger than those at the rest sections along the spanwise direction. Under the condition of RFVS at the mid-span, the smaller flow rate make the smaller difference of pressure pulsation amplitudes in the spanwise direction. Moreover, the rotating stall, rotating at 35.7%-62.5% of the runner rotational frequency, make the low frequency components of pressure pulsations distribute unevenly along the circumference in the vaneless space. However, it have little influence on the distributions of high components.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2005년도 학술발표회(1)
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• pp.250-251
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• 2005

• 한국해양공학회지
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• 제26권4호
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• pp.37-41
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• 2012

Due to global warming, the need to secure alternative resources has become more important nationally. Because of the very strong current on the west coast, with a tidal range of up to 10 m, there are many suitable sites for the application of TCP (tidal current power) in Korea. In the southwest region, a strong current is created in the narrow channels between the numerous islands. A rotor is an essential component that can convert tidal current energy into rotational energy to generate electricity. The design optimization of a rotor is very important to maximize the power production. The performance of a rotor can be determined using various parameters, including the number of blades, shape, sectional size, diameter, etc. There are many offshore jetties and piers with high current velocities. Thus, a VAT (vertical axis turbine) system, which can generate power regardless of flow direction changes, could be effectively applied to cylindrical structures. A VAT system could give an advantage to a caisson-type breakwater because it allows water to circulate well. This paper introduces a multi-layer vertical axis tidal current power system. A Savonius turbine was designed, and a performance analysis was carried out using CFD. A physical model was also demonstrated in CWC, and the results are compared with CFD.