Multiphysics Simulation, Analysis and Design of a Permanent Magnet Excited Liquid Metal Magnetohydrodynamic Power Generator

Magnetohydrodynamic (MHD) power generation is a method of mechanical to electrical energy conversion, highly researched in the 1960s. Thermal constraints and lack of powerful simulation tools brought advancements in the field to a halt. This dissertation is an attempt to revive MHD, adapting it for renewable energy harvesting and making it thus attractive for inclusion in the energy mix of the near future.

The presented work includes a detailed description of a permanent magnet excited liquid metal (PMLM) MHD generator and its operation, proposing Gallium as the working fluid. Furthermore, multiphysics simulations are used to demonstrate the validity of the analytical derivations of operating characteristics. Experimental measurements of a PMLM MHD generator prototype are provided and used to verify the multiphysics simulation method. A good match between experiments and simulation is observed as well as efficiencies up to 67%, depending on design. Optimal design considerations are included, to demonstrate the feasibility of this mechanical to electrical energy conversion method. Lastly, a case study is presented in which MHD is used for thermal to electrical energy conversion, harvesting low temperature waste heat. This thermal to electrical energy conversion reaches efficiencies up to 25%, depending on design parameters.