Numerical analysis and wave tank validation on the optimal design of a two-body wave energy converter

Journal Article · Tue May 28 00:00:00 EDT 2019 · Renewable Energy

DOI:https://doi.org/10.1016/j.renene.2019.05.109· OSTI ID:1659134

Martin, Dillon ^[1]; Li, Xiaofan ^[2]; Chen, Chien-An ^[2]; Thiagarajan, Krish ^[3]; Ngo, Khai ^[2]; Parker, Robert ^[2]; Zuo, Lei ^[2]

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1. Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States); Virginia Tech
2. Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States)
3. Univ. of Massachusetts, Amherst, MA (United States)

To improve the performance of a ‘point absorber’ type wave energy converter (WEC), an additional submerged body can be deployed. The submerged body can be used to increase the equivalent excitation force on the WEC, as well as provide resonance tuning. This paper presents numerical analysis and experimental validation of a two-body point absorber type WEC using a mechanical motion rectifier (MMR) based power takeoff. The two-body point absorber consists of a floating buoy connected to a neutrally buoyant submerged body via the power-takeoff. The mechanical motion rectifier and a ball screw translate the relative heave motion of the two bodies into unidirectional rotation, which in turn spins a generator. Frequency domain analysis suggests there is an optimal submerged body mass for maximum WEC power absorption. Regular wave simulations in the time domain are compared to the results obtained in the frequency domain. While the time domain and frequency domain results predict the same optimal mass ratio, time domain analysis provides a more complex and accurate power result. To validate the time domain model, experimental wave tank testing is conducted using a 1:30 scale model WEC. The experiment shows the two-body WEC can produce twice the amount of power as the single-body WEC with same floating buoy and can be further increased by PTO design and power electronics optimization. Furthermore, wave tank testing shows the two-body WEC has a capture width ratio up to 58% at 59 kW/m and 51% at 36 kW/m.

• Research Organization: Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States)
• Sponsoring Organization: Commonwealth Research Commercialization Fund (CRCF); National Science Foundation (NSF); USDOE Office of Energy Efficiency and Renewable Energy (EERE), Renewable Power Office. Water Power Technologies Office
• Grant/Contract Number: EE0007174
• OSTI ID: 1659134
• Alternate ID(s): OSTI ID: 1529007
• Journal Information: Renewable Energy, Journal Name: Renewable Energy Vol. 145; ISSN 0960-1481
• Publisher: Elsevier
• Country of Publication: United States
• Language: English

Related Subjects

16 TIDAL AND WAVE POWER
Time domain and frequency domain modelling
Two-body point absorber
Wave energy converter
Wave tank test