Newsletter  2014.1  Index

Theme : "The Conference of Fluid Engineering Division" Preface M.Oshima, Y. Takahashi, H. Yoshikawa Development of coaxial electromagnetic energy conversion device for efficient wind energy utilization Akira TANIDA, Hidemasa TAKANA (Tohoku University) Augmentation and attenuation of large-scale intermittent structures in rotating channel flow Takahiro ISHIDA (Tokyo University of Science) An attempt to measure wall shear stress fluctuation in a turbulent wall jet Takuya SAWADA, Osamu TERASHIMA, Yasuhiko SAKAI, Kouji NAGATA, Mitsuhiro SHIKIDA, Yasumasa ITO (Nagoya University) Concentration statistics near the turbulent / non-turbulent interface of a planar liquid jet with a chemical reaction Takahiro NAITO, Tomoaki WATANABE, Yasuhiko SAKAI, Kouji NAGATA, Yasumasa ITO, Osamu TERASHIMA (Nagoya University) The valuable experience of the Dreams of Flow Contest Tsubasa OZAKI, Jumpei OHKUBO, Hiroaki KOBAYASHI, Kodai FUJITA (Hokkaido University) A story of creation for Dreams of Flow Contest Kodai FUJITA, Hiroaki KOBAYASHI (Hokkaido University)   |  Back  |

 

Development of coaxial electromagnetic energy conversion device for efficient wind energy utilization

Akira TANIDA Tohoku University Hidemasa TAKANA Tohoku University

Abstract

Innovative energy conversion device has been developed for efficient wind energy utilization. In the conventional wind turbines, a constant power output is obtained by controlling the pitch angle of wind turbine blade for excessive wind power. Therefore, if the excessive wind energy can be utilized at the constant rotational speed, the rated power operation can be possible with enhanced efficiency.

In this study, the innovative electromagnetic energy conversion device has been developed for efficient wind energy utilization. This device has coaxial configuration and can be installed in the conventional wind turbines. In this device, the rotational speed of the turbine can be kept constant by controlling rotation torque by Lorentz force with electric power generation from the excessive wind energy. The liquid metal with high electrical conductivity is filled between the central axis and the outer ring electrode with the magnetic field applied in the axial direction. With the rotation of the central shaft, the liquid metal flows in the azimuthal direction. According to the Faraday’s law, the electromotive force of u×B is generated in the radially outward direction. The electric power is extracted by connecting an external load resistance between the central axis and outer ring electrode. Moreover, because the Lorentz force acting against the liquid metal flow increases the rotational torque, rotational speed can be controlled with power generation.

Experimental results show that the output electric power and rotational torque are controlled by external load resistance. For larger load resistance, rotational torque increases mainly due to increase in wall friction by Lorentz force attributing to azimuthal eddy current. On the other hand, rotational torque decreases for lower load resistance. Therefore, even when torque increases by excessive wind velocity, the turbine can be operated at a constant rotational speed by adjusting the external load resistance with electric energy extraction from excessive wind energy.

 

Key words

Magneto-hydro-dynamics, Liquid Metal, Power Generation, Wind Energy, Torque Control

 

Figures

Fig. 1 Photo of experimental setup

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Fig. 2 Cross sectional view of developed co-axial energy conversion device
for wind turbine.

Fig. 3 Motor torque as a function of rotational speed
for external load resistances of 0.05 Ω and 1.00 Ω.