Magnetohydrodynamic circulation schemes?

[Anonymous]

Anybody think about this?

In a nutshell: consider a rectangular-cross-section tube full of seawater - place powerful magnets in the top & bottom, then in the left & right walls, place conductive surfaces & run a current across them. The water will then be forced along the tube.

Would be a neat, plankton-friendly method of tank circulation, as long as (a) a chemically safe conducting surface is used, and (b) the current doesn't bother any inhabitants. I'm wondering how efficient this would be, and how strong the magnets would need to be.

 

[pwj1286]

The electricity to power those magnets would be huge, right? Worth the electricity? Na.

Though I would like to see it. It is hard to imagen magnets moving water.
_________________
Kingman Group

 

[Anonymous]

Sounds interesting, but I'm not sure I fully understand the idea.

The magnets at the top and bottom of the tube are stationary, right?

And then you're adding current to opposite sides of the tube?

Is the idea to create an alternating electromagnetic field that will act on the water? If so, how would that work? Sorry, lots of questions.

I guess I'm not sure what force is acting on the water to make it flow. Have time to whip up a basic diagram?

 

[Anonymous]

Here are a couple of links:

http://scitation.aip.org/journals/doc/P ... 410_1.html
http://www.stfrancis.edu/acca/accaweb05 ... e_phys.pdf

 

[Anonymous]

Very interesting. I've never heard of a process like this before.
But skimming the first link there I saw that the electrical current comes into direct contact with the fluid, resulting in electrolysis, and breaking H2 from 0. Or, from 1st link above:

"As the students can clearly observe, the boat produces many bubbles and the associated noise. The bubbles are hydrogen and oxygen being liberated through electrolysis as the current passes through the water. This propulsion system is anything but silent. The second myth is that it is nondetectable. Setting sound considerations aside, the system produces a jet of chlorine ions and metal chlorides that pour out the back of the boat. "

The chlorine doesn't sound good, LOL.

 

[Anonymous]

Chlorine gas is always a problem with applying direct current in a seawater environment unless the voltage is carefully controlled.

>...Is the idea to create an alternating electromagnetic field that will act on the water? ...

After reading the first link, you probably know that AC will not work. It will just vibrate the water back and forth, at the frequency of the driving current.

 

[Brian5000]

I've seen something like that before as an idea for water cooling in computers. I guess magnets drive ions in the water which, in turn, push the water. I think their getting pretty efficient at it too.
_________________
Mercedes CLK GTR

 

[dogstar74]

Magnets near my Hard Drive?! I don't think so!

 

[Anonymous]

There is a very powerful magnet in every modern harddrive. Take one apart, and take a look.