Theoretical investigation of a novel three-phase alternating current liquid metal vortex magnetohydrodynamic generator

Abstract

Magnetohydrodynamic (MHD) generators are a class of devices that directly convert mechanical energy of a flowing fluid into electrical energy. However, due to the production of low magnitude voltages at low fluid velocities, they are not very useful for harvesting energy from the everyday environment at a watt scale. This work theoretically investigates a novel three-phase alternating current liquid metal vortex MHD, capable of generating power on a scale of watts and voltages on a scale of volts from a wide range of environmental energy sources. A new theoretical approach is utilized, where the induced fields and the stator fields are calculated independently which makes it easy to analyze different operational modes of the system. Two limiting approximations namely duct flow and disk flow have been analyzed and the effect of the number of poles and of the electromagnetic slip on the generated power and current is studied. The obtained analytical and numerical results are in good agreement and provide a robust foundation for the generator design and experimental characterization. The formulated approach also shows that such MHD devices can be easily scaled for various applications requiring power in a range from mW to W.