MHD Generators - What electrodes to use?

Click For Summary

Discussion Overview

The discussion revolves around the selection of electrodes for an AC saltwater MHD (Magnetohydrodynamic) generator, focusing on efficiency and corrosion resistance. Participants explore various materials and their suitability for the specific conditions of the generator.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Experimental/applied

Main Points Raised

  • One participant inquires about the best type of electrodes for an AC saltwater MHD generator, emphasizing the need for efficiency and corrosion resistance.
  • Another participant suggests considering tungsten welding rods, which they have used for plasma probes, as a potential electrode material.
  • A different participant notes the importance of experimentation, indicating that materials considered corrosion resistant may not perform as expected under specific conditions of the apparatus.
  • There is a question about whether the goal is to measure flow or propulsion, with a suggestion that industrial magnetic flowmeters typically use materials like stainless steel or titanium.
  • One participant expresses openness to experimenting with different materials for their proof of concept project.
  • Another participant advises using AC to prevent plating from seawater onto the electrodes and to avoid electrolytic voltages.

Areas of Agreement / Disagreement

Participants express various viewpoints on electrode materials and their properties, with no consensus reached on a specific solution. The discussion includes multiple competing suggestions and considerations.

Contextual Notes

Participants mention the need for experimentation and the variability of material performance under different conditions, highlighting the complexity of selecting appropriate electrodes for the MHD generator.

Who May Find This Useful

Individuals interested in MHD generators, experimental physics, materials science, and those working on related engineering projects may find this discussion relevant.

Custom1
Messages
4
Reaction score
0
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
 
Engineering news on Phys.org
Custom1 said:
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

Welcome to the PF.

What have you found in your research/reading so far?
 
Custom1 said:
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
Do you have access to tungsten welding rods? We used those for all kinds of plasma probes.
 
I don't currently have access to tungsten welding rods but I can sure buy some on ebay.

Thanks!
 
Custom1 said:
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
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?
 
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

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

Similar threads

A question regarding power generation in MHD method
  • · Replies 0 ·
Replies
0
Views
1K
Undergrad Trying to create MHD drive for a boat
  • · Replies 6 ·
Replies
6
Views
2K
Electrolysis using a single electrode
  • · Replies 3 ·
Replies
3
Views
2K
AC and Electrolysis
  • · Replies 11 ·
Replies
11
Views
1K
Graduate Resistance Force on Gas in Magnetohydrodynamic Generator
  • · Replies 2 ·
Replies
2
Views
2K
Uniform Field Gap (Rogowski profile) Electrode Design
  • · Replies 3 ·
Replies
3
Views
4K
Voltaic cell + battery in series
  • · Replies 3 ·
Replies
3
Views
2K
Graduate Mystery Voltage: Investigating a Strange Phenomenon in MHD Testing
  • · Replies 6 ·
Replies
6
Views
2K
MHD Generator Performance with Ionised Gas
  • · Replies 8 ·
Replies
8
Views
2K
Measuring Power output of DC generator
  • · Replies 38 ·
2
Replies
38
Views
6K