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MHD Generators - What electrodes to use?

  1. Sep 18, 2014 #1
    Hi everyone,

    What type of electrodes should I use for an AC saltwater MHD generator? I need something that is efficient yet corrosive resistant.

  2. jcsd
  3. Sep 18, 2014 #2


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    Staff: Mentor

    Welcome to the PF.

    What have you found in your research/reading so far?
  4. Sep 18, 2014 #3
    Do you have access to tungsten welding rods? We used those for all kinds of plasma probes.
  5. Sep 21, 2014 #4
    I don't currently have access to tungsten welding rods but I can sure buy some on ebay.

  6. Sep 22, 2014 #5


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    Staff: Mentor

    I think you should be prepared to have to experiment; what is normally thought of as being corrosion resistant my not be in the particular conditions experienced in your apparatus. (I'm making a general comment about electrodes in general.)

    You have a steady flow of brine, and will pipe it through an alternating magnetic field? Is that how it works? A pair of electrodes in the pipe wall will pick off the AC voltage. Are you making something substantial, or a "proof of concept" student demo?
  7. Sep 22, 2014 #6

    jim hardy

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    Is your goal measurement of flow or propulsion ?

    Industrial magnetic flowmeters use materials like stainless or titanium, see page 7 here:
    http://w3app.siemens.com/mcms/infocenter/dokumentencenter/sc/pi/Documentsu20Brochures/E20001-A450-P710-V2-7600.pdf [Broken]

    The ones i've seen were small, maybe 2 inch pipe. They used high impedance amplifiers to pick off the millivolt signal. They were my first encounter with concept of "driven shield"..
    Last edited by a moderator: May 7, 2017
  8. Sep 22, 2014 #7
    I am not a student but it is more of a proof of concept small scale project. I'm open to experimentation of different materials. Any uggestions?
  9. Sep 22, 2014 #8
    Hi Jim,

    It is measurement of flow. I will certainly try your suggestions.

    Sorry for not quoting people I have been replying to. I'm on my phone and the quote button isn't working properly. I hope I'm not confusing anyone.
  10. Sep 22, 2014 #9

    jim hardy

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    i think you should use AC so as to not plate anything out of the seawater onto your electrodes and to avoid electrolytic voltages.
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