The Defense Advanced Research Projects Agency (DARPA) has launched a new program that seeks to create novel electrode materials suitable for a militarily significant magnetohydrodynamic (MHD) drive.
The Principles of Undersea Magnetohydrodynamic Pumps (PUMP) program will run over 42 months and will assemble and validate multi-physics modeling and simulation tools including hydrodynamics, electrochemistry, and magnetics for scaling MHD designs.
The goal of the program is to determine an electrode material system and prototype an MHD drive that could be scaled up.
“The best efficiency demonstrated in a magnetohydrodynamic drive to date was 1992 on the Yamato-1, a 30m vessel that achieved 6.6 knots with an efficiency of around 30% using a magnetic field strength of approximately 4 Tesla,” said Susan Swithenbank, PUMP program manager in DARPA’s Defense Sciences Office. “In the last couple years, the commercial fusion industry has made advances in rare-earth barium copper oxide (REBCO) magnets that have demonstrated large-scale magnetic fields as high as 20 Tesla that could potentially yield 90% efficiency in a magnetohydrodynamic drive, which is worth pursuing. Now that the glass ceiling in high magnetic field generation has been broken, PUMP aims to achieve a breakthrough to solve the electrode materials challenge.”
A major problem when electric current, magnetic field, and saltwater interact is the development of gas bubbles over the electrode surfaces. The bubbles reduce efficiency and can collapse and erode the electrode surfaces. PUMP will address different approaches to reduce the effect of hydrolysis and erosion. The program also will enable modeling of interactions between the magnetic field, the hydrodynamic, and the electrochemical reactions, which all happen on different time and length scales.
“We’re hoping to leverage insights into novel material coatings from the fuel cell and battery industries, since they deal with the same bubble generation problem,” Swithenbank added. “We’re looking for expertise across all fields covering hydrodynamics, electrochemistry, and magnetics to form teams to help us finally realize a militarily relevant scale magnetohydrodynamic drive.”