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Innovative Elastomer Transducer Driven by Karman Vortices in Water Flow



Author(s)

Seiki Chiba¹, Kenta Hasegawa², Mikio Waki³, Koji Fujita⁴, Kazuhiro Ohyama⁵ and Shijie Zhu⁵

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DOI:10.17265/2161-6213/2017.5-6.002

1. Chiba Science Institute, 3-8-18 Yakumo, Meguro-Ward, Tokyo 152-0023, Japan
2. National Maritime Research Institute, 6-38-1 Shinkawa, Mitaka-City, Tokyo 181-0004, Japan
3. Wits Inc., 880-3 Oshiage, Sakura-City, Tochigi 329-1334, Japan
4. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Sagamihara City, Kanagawa 252-5210, Japan
5. Fukuoka Institute of Technology, Fukuoka-City, Fukuoka 811-0295, Japan

A simple experimental model of a power generation system was tested in a flowing water tank in order to investigate the performance and feasibility of a small hydroelectric generation system using DE (dielectric elastomer) transducer. The mass of DE material in the power generator module was only 0.1 g. The electric energy generated with a stroke of 10 mm was 12.54 mJ. An electrical energy of approximately 1.5 J per cycle of DE generators can be expected to be generated by scaling up this system, which is capable of being equipped with up to about 100 units of DE transducers. The water velocity was set at 0.30 to 0.70 m/s. This is a small flow, about the same flow as the water in a Japanese garden. This system was driven by Karman vortices in the wake of a cylinder fixed in the water flow. The characteristics of DEs can be utilized to produce electric power effectively. A wing, which is an important part in the generation system to convert fluid energy into mechanical energy, was set behind the cylinder. The wing oscillated due to the pressure caused by Karman vortices, resulting in stretching and contracting of the DE transducers, thus producing electrical power. Experimental results show that an average output power of approximately 31 mW was produced with a generation efficiency of about 66%, when the diameter of the cylinder is 60 mm, the span and chord length of the wing are 120 mm and 30 mm, respectively, the distance between the cylinder and the wing is 170 mm, and the velocity of the water flow is 0.50 m/s.

Artificial muscle, actuator, DE, hydro power generation, wing power generation, Karman vortex.