• 한국해양공학회지
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• 제20권2호
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• pp.22-28
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• 2006

The motion and wave drift forces of floating BBDB (backward-bent duct buoy) wave energy absorbers in regular waves are calculated, taking account of the oscillating surface-pressure due to the pressure drop in the air chamber above the oscillating water column, within the scope of the linear wave theory. A series of model tests has been conducted in order to order to verify the motion and time mean wave drift force reponses in regular waves at the ocean engineering basin, MOERI/KORDI. The pneumatic damping through an orifice-type duct for the BBDB wave energy device are deducted from experimental research. Numerical simulation for motion and drift force responses of the BBDB wave energy device, considering pneumatic damping coefficients, has been carried out, and the results are compared with those of model tests.

• 한국산업융합학회 논문집
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• 제23권6_2호
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• pp.999-1006
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• 2020

This study was conducted to develop an efficiency prediction program of a hydraulic secondary energy converter for calculating annual power generation of a Wavestar type wave power generator. Using the period and wave height obtained from the frequency domain analysis, the behavior of the floating body was obtained by assuming the sin function. The piston displacement and speed of the hydraulic cylinder were calculated considering the behavior of the floating body and the shape of the mechanism. The numerical simulation of the hydraulic system was performed by physically modeling the hydraulic cylinders, check valves, hydraulic motors, which are the main devices. In the future, this analysis program will be used to develop a program for estimating annual power generation of a moveable body type wave power generation device.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2011년도 춘계학술대회 초록집
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• pp.167.1-167.1
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• 2011

Sustainable energy generation is becoming extremely imperative due to the expected limitations in current energy resources and to reduce pollution. Especially, because of its considerable energy potential, ocean wave energy has been investigated with regard to power generation. To develop large high power wave generator system, it is important to make a small scale proto type and to test that. Thus the objective of this research is to examine the characteristics of a mechanically excited generator system having small power capacity experimentally. The water reservoir (4 m length, 1.5 m width and 1.8 m depth) having a wave maker to make arbitrary height and period of the water wave was made. The proto type consists of three main parts; a buoy, rack-pinion base one-way mechanism, and a wave generator(Fig.1). The water wave is going up and down and the hexahedron buoy is following the wave. The rack gear attached to the buoy is also going up and down to roll the pinion connected to an electric generator then it produces electricity. The experiments were performed with several conditions of water waves, and the power outputs over 30 W could be measured for some conditions. In future works, to achieve higher performance for the proto type, the effects of primary parameters (buoy shape and mass, etc.) on the system efficiency will be identified.

• 한국해양환경ㆍ에너지학회지
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• 제18권4호
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• pp.291-297
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• 2015

10 MW급의 파력-해상풍력 복합발전 플랫폼 설치해역으로 고려되고 있는 차귀도 해역에서 측정된 파랑정보를 이용하여 파랑스펙트럼을 구하고, 이로부터 생성된 불규칙파에 따라 수직 운동하는 파력발전기에 Sheng et al.(2015)이 제안한 래칭 제어기법을 적용하였다. 래칭 시간을 정할 때 필요한 입사파의 주기로 불규칙파의 통계 대푯값인 피크 주기를 사용하였다. 래칭 제어기법을 불규칙파중 부이의 시간영역 해석에 적용한 결과, 약 50%의 추출파워의 증가를 가져왔다.

• 한국해안·해양공학회논문집
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• 제26권2호
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• pp.103-111
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• 2014

크기가 작은 다수의 부이들이 원형으로 배열되어 있을 때 부이를 통한 추출 파워를 포텐셜이론 통하여 살펴보았다. 부이의 크기와 배열 간격이 수심과 파장 그리고 설치면적의 반경에 비하여 작다는 가정 아래에서 다수부이로 채워진 수면에서의 경계조건식을 유도하고 이를 포함한 경계치문제를 고유함수전개법을 이용하여 해석하였다. 추출 파워와 입사파 에너지의 비인 취득 폭을 packing ratio, 배열 반경, 그리고 PTO 감쇠계수를 바꿔가면서 살펴보았다. 또한 다수의 소형 부이를 원형 배열하였을 때 추출된 파력이 같은 잠긴 체적을 갖는 대형 단일 부이보다 효율적임을 계산을 통하여 밝혔다.

• 전기학회논문지
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• 제60권12호
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• pp.2260-2264
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• 2011

This paper describes the development of an wave energy convertor. We devise a new type of the wave energy convertor which generates electricity by means of under-water pressure oscillation. This wave energy convertor is installed on the seabed floor. That is, there is no exposed body on the surface of the sea. The wave energy convertor comprises an activated assembly which is adapted to be displaced in response to water pressure oscillation to vary the volume of bellows cavity and a power take off assembly which generates electricity in response to movement of the activated assembly.

• 수산해양교육연구
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• 제27권5호
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• pp.1303-1309
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• 2015

The behavior and flow characteristics of the floating wave energy converter were analyzed by using CFD in this study. The average significant wave height was confirmed as 0.5~2.0m from the Korean coastal sea area. This study was carried out by selecting a range of 1.0~1.6m in the wave height to simulate the operations of realistic wave energy converter system. The principle of a piston wave maker was applied in order to produce periodic wave. The behavior of the wave energy converter and the state of the wave overtopping according to the generated periodic wave were confirmed through the unsteady three-dimensional flow analysis. It was found that the wave overtopping rate according to the generated periodic wave was in range of the 11.6~30.0 kg/s.

• 동력기계공학회지
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• 제17권2호
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• pp.103-107
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• 2013

The structure of a variable liquid column oscillator(a VLCO) is analogous to that of the tuned liquid column damper used to suppress oscillatory motion in large structures like tall buildings and cargo ships. The VLCO is a system absorbing high kinetic energy of accelerated motions of multiple floating bodies in the effect of air springs occurred by installation of inner air chambers. Thus, VLCO can improve the efficiency of energy than wave energy converters of the activating object type made in Pelamis Company. In this research, the experiment was performed that a simple floating body was filled with internal fluid of same draft. The characteristics of motions were evaluated in each case of the opening or closing of the upper valves.

• 동력기계공학회지
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• 제18권3호
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• pp.36-41
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• 2014

The structure of a variable liquid column oscillator(a VLCO) is analogous to that of the tuned liquid column damper used to suppress oscillatory motion in large structures like tall buildings and cargo ships. The VLCO is a system absorbing high kinetic energy of accelerated motions of the multiple floating bodies in the effect of air springs occurred by installation of inner air chambers. Thus, VLCO can improve the efficiency of energy than wave energy converters of the activating object type made in Pelamis Company. In this research, the experiment was performed in two models of same draft. The one is that weights were filled, and the other is that water was filled. The numerical results were estimated by assuming that do not exist internal flow, and the results were compared with the results of experiments.

• 한국해양환경ㆍ에너지학회지
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• 제17권3호
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• pp.182-188
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• 2014

진동수주형 파력발전시스템의 성능은 OWC챔버의 형상 뿐만 아니라 입사파의 각도와 터빈의 효과로 인한 압력강하등과 같은 작동환경의 영향도 받는다. 기존의 대부분 연구들은 파랑에너지 흡수효율에 초점을 맞췄기 때문에 입사파 방향이 OWC챔버 입구면과 직각을 이룬다는 가정 하에 수행되었다. 하지만 실해역에서는 입사파가 해양환경에 따라 사파의 형태로 입사하게 될 것이고, 고정식 구조물인 경우에는 그 영향이 더욱 지배적이다. 본 논문은 실험 및 수치해석적인 방법으로 사파중 OWC챔버의 성능에 대하여 고찰하였다. 실험은 3차원 조파수조를 이용하여 다양한 입사파 각도조건에서 수행하였다. 터빈의 영향을 고려하기 위하여 오리피스를 적용하여 챔버내 진동수주의 수위 변동을 계측하였다. VOF모델을 기반으로 한 수치조파수조를 구축하여 실험과 동일한 조건으로 계산을 수행하여 실험결과와 비교분석하여 공기실과 그 인근의 유동변화를 고찰하였다.