A Comparative Study on the Performance of Marine Magnetohydrodynamic Motors With Helical and Linear Channels

A magnetohydrodynamic (MHD) thruster is a type of electric motors which moves electrically conductive fluids without any mechanical moving parts. In this study, a linear-type MHD thruster is compared with a helical-type MHD thruster that has the same channel length and volume. For this purpose, two analytical models are used to predict the behaviors of these two types of marine MHD thrusters. The analytical model used for the helical thruster is validated by comparison to the experimental data obtained by other researchers. To validate the analytical model used for the linear thruster, a thruster prototype is manufactured and tested. The results show that although the solenoid magnet of the helical-type thruster is much easier to get a higher magnetic flux density than the saddle-shaped magnet of the linear-type thruster, the efficiency and propulsion force density of the linear-type thruster are much better than those of the helical-type one. Therefore, the linear-type thrusters cannot be ignored simply because of the complexity of their coils.