Fundamental studies of helical-type seawater MHD generation system

A new MHD (magnetohydrodynamics) generator based on electromotive force using seawater, that is, a helical-type seawater MHD generator with a 7 T solenoid superconducting magnet, is designed, constructed and tested. The constructed generator contains a helical insulation wall made of polyvinyl chloride 140 mm long and 100 mm in diameter, an anode rod made of SUS316 1350 mm long and 10 mm in diameter, and a cathode pipe made of SUS316 260 mm long and 100 mm in diameter. In the experiment, electromotive force and generator output are measured in terms of average flow velocity (0-5.6 m/s) and magnetic field (0-7 T) using artificial seawater (3.4% NaCl aqueous solution). As a result of the experiment, it was found that the electromotive force increases proportionally to average flow velocity and magnetic field, and that the generator output increases quadratically to average flow velocity and magnetic field over certain points. Experimental values are discussed by comparing the theoretical values and computed values.