Elementary study on superconducting electromagnetic ships with helical insulation wall Original Research Article

We, Kobe University of Mercantile Marine (KUMM) and Institute of Electrical Engineering (IEE) research teams, have carried out in Japan, the joint experimental test of the high magnetic field (∼14 T) superconducting electromagnetic ship performance in co-operation with the researchers of NRIM. In this experimental study, the major system components are thruster, seawater circulating system and various measuring instruments. The NRIMs 15 T class superconducting magnet that forms the outmost member of the 40 T class hybrid magnet was used. The flow guide and flow rectifier are of same lengths of 0.2 m, and the length of the electrodes are 0.6 m. The anodeʹs outer diameter is 0.1 m, and the cathodeʹs inner diameter is 0.346 m. The helical insulation wall is 10 mm thick and the pitch number is 3.8. During the experiment, magnetic fields were changed to six stages 3, 5, 8, 10, 12 and 14 T, whereby seawater pressures, temperatures and flow rates were measured. Electric currents were changed from 10 to 700 A. In one of results, the thruster efficiency increases in association with the increase of the magnetic field. It has been demonstrated that the helical-type superconducting electromagnetic thruster is superior, in terms of thruster efficiency, than that of earlier works by Iwata et al. and YAMATO-1ʹs group. So, it is considered that this thruster is better suited to commerical application than earlier works.