MHD (MagnetoHydroDynamic) Propulsion for submarines

[Forest Green]

Le ministère des Armées planche sur une technologie de rupture pour la propulsion des sous-marins - Zone Militaire

Pour mener à bien ses missions, un sous-marin nucléaire doit être le plus discret possible. Seulement, malgré les innovations développées au cours de ces

www.opex360.com

To eliminate this cavitation noise, there is only one solution: do without a propeller... Which would be possible with magnetohydrodynamics [MHD] which, to summarize succinctly, is concerned with the flow of electrically conductive fluids in the presence of a magnetic field.

“The basic principle of MHD propulsion is simple. It involves using electromagnetic forces to propel ships by reaction. These Laplace forces come from the interaction between a magnetic field, created by superconducting coils and electric currents circulating in sea water. Thus, the electrical energy, supplied by generators on board, is directly transformed into mechanical energy [work of electromagnetic forces],” explains Christophe Trophime, in a thesis on this subject.

 

[Hydroman]

I assume the magnetic field would be quite large along with the power required to generate an efficient propulsive force, wouldn't this leave the sub vulnerable to magnetic detection sensors? You would probably have to shield a good portion of the hull as well which could add lots of additional weight, not unless new types of shielding materials of active field cancellation tech (underway deperming) is being developed.

 

[Forest Green]

I assume the magnetic field would be quite large along with the power required to generate an efficient propulsive force, wouldn't this leave the sub vulnerable to magnetic detection sensors? You would probably have to shield a good portion of the hull as well which could add lots of additional weight, not unless new types of shielding materials of active field cancellation tech (underway deperming) is being developed.

You can detect objects via magnetic field anyway it seems:

Atomic magnetometers detect underwater objects – Physics World

Technique is very difficult to evade, say physicists

physicsworld.com

I'm guessing it boils down to detection ranges. Acoustic signature travels a long way underwater but at the sort of ranges magnetic fields could be detected, it's already well within acoustic detection range anyway. It's a, "well can't a stealth aircraft still be seen by Mk1 eyeball and IR?" kind of scenario.

 

[TomcatViP]

You can do that internally, within a shielded chamber, with an inlet and an actuator and then neutralize the charge with a depletive electrons source.
Nothing new here in the basic principle. This has been around since the 60's.
Actuation of seawater was big again in the early 2000s. Glad it comes back.

 

[greenmartian2017]

Just saw this on Youtube, about the USS Montana being refitted with an MHD drive and to undergo tests on the Penobscot river in Maine.
I can't say whether this is accurate reporting, or not. But someone else might have a better clue than me as to its veracity.

View: https://www.youtube.com/watch?v=GFJrmF7Cdbg
.

 

[A Tentative Fleet Plan]

Just saw this on Youtube, about the USS Montana being refitted with an MHD drive and to undergo tests on the Penobscot river in Maine.
I can't say whether this is accurate reporting, or not. But someone else might have a better clue than me as to its veracity.

View: https://www.youtube.com/watch?v=GFJrmF7Cdbg
.

Just a YouTube account parroting a Naval News April Fools article.

 

[TomS]

Apparently quite a few sites fell for that one.

Media Outlets Sunk By April Fool's Prank of the Navy's New "Caterpillar Drive" Stealth Submarine

Reports about a new stealth submarine with an advanced "caterpillar drive" sounds like something right out of a Tom Clancy novel... because it is.

thedebrief.org

 

[Scott Kenny]

I assume the magnetic field would be quite large along with the power required to generate an efficient propulsive force, wouldn't this leave the sub vulnerable to magnetic detection sensors? You would probably have to shield a good portion of the hull as well which could add lots of additional weight, not unless new types of shielding materials of active field cancellation tech (underway deperming) is being developed.

You can detect something using magnets of the strength necessary to shove a submarine around from miles away on a magnetometer.

We're not talking about MRI magnets here, or if we are talking about magnets that weak they're in a circle some 3m/10ft across the inner opening.

 

[greenmartian2017]

Apparently quite a few sites fell for that one.

Media Outlets Sunk By April Fool's Prank of the Navy's New "Caterpillar Drive" Stealth Submarine

Reports about a new stealth submarine with an advanced "caterpillar drive" sounds like something right out of a Tom Clancy novel... because it is.

thedebrief.org

I thought it was super odd to try to test a submarine in the Penobscot river....it just didn't smell right to me. I was wondering how deep it was, and whether it could sustain a submersed submarine, and whether its width for such a sub could be sustained (including a turnaround radius)....that's why I was cautious and wondered if this was accurate or not.

But thanks for pointing the piece's origins.