Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

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.

    Thanks
     
  2. jcsd
  3. Sep 18, 2014 #2

    berkeman

    User Avatar

    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.

    Thanks!
     
  6. Sep 22, 2014 #5

    NascentOxygen

    User Avatar

    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

    User Avatar
    Science Advisor
    Gold Member
    2016 Award

    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

    User Avatar
    Science Advisor
    Gold Member
    2016 Award

    i think you should use AC so as to not plate anything out of the seawater onto your electrodes and to avoid electrolytic voltages.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: MHD Generators - What electrodes to use?
Loading...