Fully 3-D Numerical Investigation of Phenomena Occurring in Marine Magnetohydrodynamic Thrusters

A magnetohydrodynamic (MHD) thruster is a type of electric motor which does not have mechanical moving parts and directly converts electrical energy into mechanical energy. In this paper, a multiphysics numerical simulation has been performed to investigate the phenomena occurred in the channel of marine MHD thrusters. In this simulation, all electric, magnetic, and fluid flow fields have been considered 3-D. For this purpose, a marine MHD thruster model with saddle-shaped coils is selected, and its dimensions are determined. Then, this thruster is simulated numerically, and its electromagnetic and fluid flow parameters are studied. In this simulation, the effects of seawater electrolysis and end loss are taken into account. An experimental setup is established to validate the results obtained from the numerical simulation. The results reveal that the nonuniformities of the electric and magnetic fields along the channel have a great impact on the performance of the thruster. Unlike the results obtained in the previous studies, it is shown that the velocity near the electrodes is higher than that near the sidewalls arisen from the higher electromagnetic force close to the electrodes.