We investigate the feasibility of using Magneto-Hydrodynamics (MHD) to implement a propeller-less propulsion system. The basic principle behind MHD is to use the (Lorentz) force produced by the interaction of electric and magnetic fields to generate thrust on a conducting fluid in motion. Electrodes are lined up along the walls of the duct which act as the source of the electric field. Sea-water acts as the conducting medium for the current when it passes through the duct. This medium is then subjected to a strong magnetic field within the duct, thereby producing an axial force, i.e. an axial thrust. Propulsion systems based on MHD require virtually no mechanical components; therefore, a good application would be to design a propulsor which produces very little noise for small underwater vehicles. Results of a preliminary feasibility study on this application are presented in this paper. An approximate, consistent model to estimate the propulsion performance of a MHD propulsor for small underwater vehicles is introduced and analyzed. The model is generalized from the hydrodynamic point of view to consider inlet and outlet convergent/divergent nozzles. The general model is applied systematically varying the main design parameters considering a small autonomous underwater vehicle (AUV). Results show that non trivial trade-off conditions exist between inlet and outlet geometry, number of MHD channels, applied magnetic field and voltage, as the vehicle speed changes, to get the highest propulsion efficiency.
Application Perspectives of Magneto-Hydro-Dynamics To Propel Autonomous Underwater Vehicles
Bansal, Parth, and Stefano Brizzolara. "Application Perspectives of Magneto-Hydro-Dynamics To Propel Autonomous Underwater Vehicles." Paper presented at the SNAME Maritime Convention, Providence, Rhode Island, USA, October 2018.
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