Editing Magnetohydrodynamics (section)

=== Engineering ===

MHD is related to engineering problems such as [[fusion power|plasma confinement]], liquid-metal cooling of [[nuclear reactor]]s, and [[Electromagnetism|electromagnetic]] casting (among others).

A [[magnetohydrodynamic drive]] or MHD propulsor is a method for propelling seagoing vessels using only electric and magnetic fields with no moving parts, using magnetohydrodynamics. The working principle involves electrification of the propellant (gas or water) which can then be directed by a magnetic field, pushing the vehicle in the opposite direction. Although some working prototypes exist, MHD drives remain impractical.

The first prototype of this kind of propulsion was built and tested in 1965 by Steward Way, a professor of mechanical engineering at the [[University of California, Santa Barbara]].  Way, on leave from his job at [[Westinghouse Electric (1886)|Westinghouse Electric]], assigned his senior-year undergraduate students to develop a submarine with this new propulsion system.<ref>{{cite magazine |title=Run Silent, Run Electromagnetic |date=1966-09-23 |magazine=[[Time (magazine)|Time]] |url=http://www.time.com/time/magazine/article/0,9171,842848-1,00.html|archive-url=https://web.archive.org/web/20090114084102/http://www.time.com/time/magazine/article/0,9171,842848-1,00.html|url-status=dead|archive-date=January 14, 2009}}</ref>  In the early 1990s, a foundation in Japan (Ship & Ocean Foundation (Minato-ku, Tokyo)) built an experimental boat, the ''[[Yamato 1|Yamato-1]]'', which used a magnetohydrodynamic drive incorporating a [[superconductor]] cooled by [[helium|liquid helium]], and could travel at 15&nbsp;km/h.<ref name = "yamato">Setsuo Takezawa et al. (March 1995) ''Operation of the Thruster for Superconducting Electromagnetohydrodynamic Propu1sion Ship YAMATO 1''</ref>

[[MHD generator|MHD power generation]] fueled by potassium-seeded coal combustion gas showed potential for more efficient energy conversion (the absence of solid moving parts allows operation at higher temperatures), but failed due to cost-prohibitive technical difficulties.<ref>''[http://navier.stanford.edu/PIG/PIGdefault.html Partially Ionized Gases] {{webarchive|url=https://web.archive.org/web/20080905113821/http://navier.stanford.edu/PIG/PIGdefault.html |date=2008-09-05 }}'', M. Mitchner and Charles H. Kruger, Jr., Mechanical Engineering Department, [[Stanford University]]. See Ch. 9 "Magnetohydrodynamic (MHD) Power Generation", pp. 214–230.</ref> One major engineering problem was the failure of the wall of the primary-coal combustion chamber due to abrasion.

In [[microfluidics]], MHD is studied as a fluid pump for producing a continuous, nonpulsating flow in a complex microchannel design.<ref name=Nguyen>{{cite book | author=Nguyen, N.T. |author2=Wereley, S. | title=Fundamentals and Applications of Microfluidics | date=2006 | publisher =[[Artech House]] }}</ref>

MHD can be implemented in the [[continuous casting]] process of metals to suppress instabilities and control the flow.<ref>{{cite conference |last=Fujisaki |first=Keisuke |title=Conference Record of the 2000 IEEE Industry Applications Conference. Thirty-Fifth IAS Annual Meeting and World Conference on Industrial Applications of Electrical Energy (Cat. No.00CH37129) |date=Oct 2000 |chapter=In-mold electromagnetic stirring in continuous casting |doi=10.1109/IAS.2000.883188 |conference=Industry Applications Conference |publisher=IEEE |volume=4 |pages= 2591–2598 |isbn=0-7803-6401-5 }}</ref><ref>{{cite journal |last1=Kenjeres |first1=S. |last2=Hanjalic |first2=K. |date=2000 |title=On the implementation of effects of Lorentz force in turbulence closure models |journal=International Journal of Heat and Fluid Flow |volume=21 |issue=3 |pages=329–337 |doi=10.1016/S0142-727X(00)00017-5 |bibcode=2000IJHFF..21..329K }}</ref>

Industrial MHD problems can be modeled using the open-source software EOF-Library.<ref>{{Cite journal|last1=Vencels|first1=Juris|last2=Råback|first2=Peter|last3=Geža|first3=Vadims|date=2019-01-01|title=EOF-Library: Open-source Elmer FEM and OpenFOAM coupler for electromagnetics and fluid dynamics|journal=SoftwareX|volume=9|pages=68–72|doi=10.1016/j.softx.2019.01.007|issn=2352-7110|bibcode=2019SoftX...9...68V|doi-access=free}}</ref> Two simulation examples are 3D MHD with a free surface for [[Magnetic levitation|electromagnetic levitation]] melting,<ref>{{Cite journal|last1=Vencels|first1=Juris|last2=Jakovics|first2=Andris|last3=Geza|first3=Vadims|date=2017|title=Simulation of 3D MHD with free surface using Open-Source EOF-Library: levitating liquid metal in an alternating electromagnetic field|journal=Magnetohydrodynamics|volume=53|issue=4|pages=643–652|doi=10.22364/mhd.53.4.5|issn=0024-998X}}</ref> and liquid metal stirring by rotating permanent magnets.<ref>{{Cite journal|last1=Dzelme|first1=V.|last2=Jakovics|first2=A.|last3=Vencels|first3=J.|last4=Köppen|first4=D.|last5=Baake|first5=E.|date=2018|title=Numerical and experimental study of liquid metal stirring by rotating permanent magnets|url=http://stacks.iop.org/1757-899X/424/i=1/a=012047|journal=IOP Conference Series: Materials Science and Engineering|language=en|volume=424|issue=1|pages=012047|doi=10.1088/1757-899X/424/1/012047|issn=1757-899X|bibcode=2018MS&E..424a2047D|doi-access=free}}</ref>