MHD Generators - What electrodes to use?

[Custom1]

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

 

[berkeman]

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?

 

[KL7AJ]

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.

 

[Custom1]

I don't currently have access to tungsten welding rods but I can sure buy some on ebay.

Thanks!

 

[NascentOxygen]

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?

 

[jim hardy]

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"..

 

[Custom1]

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?

 

[Custom1]

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.

 

[jim hardy]

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.