Hydrokinetic energy conversion by two rough tandem-cylinders in flow induced motions: Effect of spacing and stiffness

RENEWABLE ENERGY

卷:107

Article

Sun, Hai^1,2  Ma, Chunhui^2,3  Kim, Eun Soo^2,8  Nowakowski, Gary⁴  Mauer, Erik⁵  Bernitsas, Michael M.^2,6,7 

[1] Harbin Engn Univ, Harbin, Peoples R China

[2] Univ Michigan, Marine Renewable Energy Lab, Dept Naval Architecture & Marine Engn, 2600 Draper Rd, Ann Arbor, MI 48109 USA

[3] Jiangsu Maritime Inst, Nanjing, Jiangsu, Peoples R China

[4] US DOE, Wind & Water Power Technol Off, Golden Field Off, Washington, DC 20585 USA

[5] US DOE, Allegheny Sci & Technol, Washington, DC 20585 USA

[6] Univ Michigan, Dept Mech Engn, Ann Arbor, MI 48109 USA

[7] Vortex Hydro Energy, Ann Arbor, MI USA

[8] Pusan Natl Univ, Dept Naval Architecture & Ocean Engn, Pusan 46241, South Korea

关键词: Hydrokinetic energy harnessing;    Virtual spring-damping;    Flow induced motions;    Vortex induced vibrations;    Galloping;    Distributed roughness;   

DOI  :  10.1016/j.renene.2017.01.043

来源: Elsevier

【 摘 要 】

Flow Induced Motions (FIMs) of rigid circular cylinders, and particularly VIV (Vortex Induced Vibrations) and galloping, are induced by alternating lift. The VIVACE (VIV for Aquatic Clean Energy) Converter uses single or multiple cylinders, in tandem, on elastic end-supports, in synergistic FIM, to convert MHK energy to electricity. Selectively distributed surface roughness is applied to enhance FIM and increase efficiency. In this paper, two cylinders are Used in tandem with center-to-center spacing of 1.57, 2.0 and 2.57 diameters, harnessing damping ratio 0.004< 0.24, for Reynolds number 30,000 < Re < 120,000. The virtual spring-damping system V-ck in the Marine Renewable Energy Laboratory (MRELab) enables embedded computer-controlled change of viscous-damping and spring-stiffness for fast and mathematically correct oscillator realization, without including the hydrodyllamic force in the closed control loop. Experimental results for oscillatory response, energy harvesting, and efficiency are presented and the envelope of optimal power is derived. All the experiments were conducted in the Low Turbulence Free Surface Water (LTFSW) Channel of the MRELab of the University of Michigan. The main conclusions are: (1) For the tested cylinder spacing, two cylinders harness power is between 2.56 and 13.49 times the power of a single cylinder, the efficiency of two cylinders is between 2.0 and 6.68 of a single cylinder. (2) The MHK power harnessed by the upstream cylinder is increased by up to 100%, affected by the downstream cylinder. (3) The MHK power harnessed by the downstream cylinder and its FIM are affected to a lesser extent by the interaction. (4) VIVACE can harness energy from flows as slow as 0.4 m/s with no upper limit in flow velocity. (5) Close spacing and high spring Stiffness yield highest harnessed power. (6) The optimal harnessed power shifts to softer springs as spacing increases. (C) 2017 Elsevier Ltd. All rights reserved.

【 授权许可】

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