Ferrofluid
Moderator: scott
Ferrofluid
if you were to take a lot of ferrofluid, and put it on a strong rare earth magnet, then put the right half of a vertical wheel into the fluid, would it rotate due to the ferrofluid side being denser than air side?
re: Ferrofluid
Flywheel,
you do not state what material the wheel is composed of. IMO the answer is no. the carrier or main ingredient to Ferrofluid is mineral oil. To make the wheel turn it would have to absorb the oil and then dissipate it on the ascending side.
http://www.wondermagnet.com/ferro.html
http://www.google.com/search?ie=UTF-8&o ... Ferrofluid
Ralph
you do not state what material the wheel is composed of. IMO the answer is no. the carrier or main ingredient to Ferrofluid is mineral oil. To make the wheel turn it would have to absorb the oil and then dissipate it on the ascending side.
http://www.wondermagnet.com/ferro.html
http://www.google.com/search?ie=UTF-8&o ... Ferrofluid
Ralph
re: Ferrofluid
Good guess Flywheel, but it won't work. Click here to find out why.
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ken_behrendt
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re: Ferrofluid
Flywheel...
Thanks for your question about ferrofluid powered devices.
It got me to thinking about how it might be possible to use this unusual substance to provide a wheel with a continuous driving torque. What I came up with is attached below.
Basically, it consists of a non-magnetic wheel which has a large number of non-magnetic pins attached near its rim that project away from the plane of the wheel at right angles. There could even be two discs with the pins between them to form something that would look like one of Georg's "Hamster cages".
At four locations 90° apart from each other near the wheel's rim are located bar magnets with square cross sections. Sticking to the north pole face of each magnet is a blob of ferrofluid material. The magnets are carefully positioned so that the pins on the wheel will, then the wheel turns, intercept the air/ferrofluid boundary nearest the pole faces of the magnet.
Now, since the magnetic field pulls the ferrofluid against the pole face, the internal pressure of the ferrofluid will increase as it gets closer to a pole face in a manner similar to the way water pressure increases as one's depth below sea level increases. This pressure differential will be such that it will actually apply buoyant force to one of the wheel's pins when it is immersed in the ferrofluid near the magnet's pole face. As a result, the pin will begin to "float" away from the pole face and, in the process, apply a torque to the wheel that will turn it!
Since the pins (and the wheel they are attached to) are non-magnetic, as a moving pin leaves the blob of ferrofluid, it will not carry any of the ferrofluid away with it. Thus, the ferrofluid blobs will remain attached to their respective magnets at all times even though the pins continuously move through them.
Anyway, IF this system is workable, then it should provide a torque which would allow the wheel to continuously undergo a slow rotation. There would be no runaway wheel acceleration because the viscous drag of the ferrofluid on the pins moving through it would impose a low terminal velocity of the wheel.
ken
Thanks for your question about ferrofluid powered devices.
It got me to thinking about how it might be possible to use this unusual substance to provide a wheel with a continuous driving torque. What I came up with is attached below.
Basically, it consists of a non-magnetic wheel which has a large number of non-magnetic pins attached near its rim that project away from the plane of the wheel at right angles. There could even be two discs with the pins between them to form something that would look like one of Georg's "Hamster cages".
At four locations 90° apart from each other near the wheel's rim are located bar magnets with square cross sections. Sticking to the north pole face of each magnet is a blob of ferrofluid material. The magnets are carefully positioned so that the pins on the wheel will, then the wheel turns, intercept the air/ferrofluid boundary nearest the pole faces of the magnet.
Now, since the magnetic field pulls the ferrofluid against the pole face, the internal pressure of the ferrofluid will increase as it gets closer to a pole face in a manner similar to the way water pressure increases as one's depth below sea level increases. This pressure differential will be such that it will actually apply buoyant force to one of the wheel's pins when it is immersed in the ferrofluid near the magnet's pole face. As a result, the pin will begin to "float" away from the pole face and, in the process, apply a torque to the wheel that will turn it!
Since the pins (and the wheel they are attached to) are non-magnetic, as a moving pin leaves the blob of ferrofluid, it will not carry any of the ferrofluid away with it. Thus, the ferrofluid blobs will remain attached to their respective magnets at all times even though the pins continuously move through them.
Anyway, IF this system is workable, then it should provide a torque which would allow the wheel to continuously undergo a slow rotation. There would be no runaway wheel acceleration because the viscous drag of the ferrofluid on the pins moving through it would impose a low terminal velocity of the wheel.
ken
- Attachments
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- Behold the "FerroFluid" Wheel!
On 7/6/06, I found, in any overbalanced gravity wheel with rotation rate, ω, axle to CG distance d, and CG dip angle φ, the average vertical velocity of its drive weights is downward and given by:
Vaver = -2(√2)πdωcosφ
Vaver = -2(√2)πdωcosφ
re: Ferrofluid
Sorry ken,
Your non-magnetic pins would have to be of a non-ferrous metal. lighter than the mass of ferrofluid. Therefore the force needed for it to penetrate the ferrofluid would be the same as the buoyant force gained upon exit. Push an air filled ball under water and then release it, it is another example of a conservative force.
Even if it did work the adhesive action of the oil in the ferrofluid would adhere to your non-magnetic rods and CF would throw it like sh-t hitting the fan!
Ferrofluid can be made at home by crushing ceramic magnets into powder and then mixing with 10 weight motor oil. Keep your fingers out of it and do not use your wifes good china to mix it in!
Ralph
Your non-magnetic pins would have to be of a non-ferrous metal. lighter than the mass of ferrofluid. Therefore the force needed for it to penetrate the ferrofluid would be the same as the buoyant force gained upon exit. Push an air filled ball under water and then release it, it is another example of a conservative force.
Even if it did work the adhesive action of the oil in the ferrofluid would adhere to your non-magnetic rods and CF would throw it like sh-t hitting the fan!
Ferrofluid can be made at home by crushing ceramic magnets into powder and then mixing with 10 weight motor oil. Keep your fingers out of it and do not use your wifes good china to mix it in!
Ralph
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ken_behrendt
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re: Ferrofluid
Ralph wrote:
As pins entered the air/ferrofluid boundary, they might feel some buoyant forces trying to prevent their entry, but these could be countered by the buoyant forces acting on other pins already immersed in the fluid. Hopefully, there would be a net force left over to drive the wheel.
The biggest problem I see with this device is the ferrofluid itself. Under the continuous attraction of the magnet, the microscopic particles of iron oxide might settle out of the silicone oil and just form a small pile on the magnet's pole face. If that happens then that will be the end of any buoyant forces acting on the pins.
ken
Actually, I am envisioning the pins and the wheel that holds them as being made from some sort of plastic material. The ferrofluid could be made from micronized iron oxide powder suspended in a medium viscosity silicone oil.Your non-magnetic pins would have to be of a non-ferrous metal. lighter than the mass of ferrofluid. Therefore the force needed for it to penetrate the ferrofluid would be the same as the buoyant force gained upon exit.
As pins entered the air/ferrofluid boundary, they might feel some buoyant forces trying to prevent their entry, but these could be countered by the buoyant forces acting on other pins already immersed in the fluid. Hopefully, there would be a net force left over to drive the wheel.
The biggest problem I see with this device is the ferrofluid itself. Under the continuous attraction of the magnet, the microscopic particles of iron oxide might settle out of the silicone oil and just form a small pile on the magnet's pole face. If that happens then that will be the end of any buoyant forces acting on the pins.
ken
On 7/6/06, I found, in any overbalanced gravity wheel with rotation rate, ω, axle to CG distance d, and CG dip angle φ, the average vertical velocity of its drive weights is downward and given by:
Vaver = -2(√2)πdωcosφ
Vaver = -2(√2)πdωcosφ
re: Ferrofluid
Ferro-fluid is cool stuff. Here's one possible variation. Please excuse the PBrush quality.
PIMAN
PIMAN
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The Sky is the Limit
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ken_behrendt
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re: Ferrofluid
PIMAN...
It's a nice sketch, but I think the arrangement you show would be unworkable.
The problem is that you will not get vertical buoyancy for the floats in the ferrofluid because the fluid is being held inside of the center holes of the ring magnets. That means that all pressure differentials within any part of ferrofluid will be horizontal and toward the nearest portion of the ring to it.
In order to obtain a vertical force of buoyancy, you need to have the ferrofluid being pulled downward toward the Earth by the magnets. Maybe the arrangement I show below would work.
ken
It's a nice sketch, but I think the arrangement you show would be unworkable.
The problem is that you will not get vertical buoyancy for the floats in the ferrofluid because the fluid is being held inside of the center holes of the ring magnets. That means that all pressure differentials within any part of ferrofluid will be horizontal and toward the nearest portion of the ring to it.
In order to obtain a vertical force of buoyancy, you need to have the ferrofluid being pulled downward toward the Earth by the magnets. Maybe the arrangement I show below would work.
ken
- Attachments
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- This looks workable to me...
On 7/6/06, I found, in any overbalanced gravity wheel with rotation rate, ω, axle to CG distance d, and CG dip angle φ, the average vertical velocity of its drive weights is downward and given by:
Vaver = -2(√2)πdωcosφ
Vaver = -2(√2)πdωcosφ
re: Ferrofluid
nice drawing! looks like it actually might work... but ferrofluid is expensive, so i wouldn't try and build it my self.
re: Ferrofluid
looks like a "perfect air/water seal" into a water tank bouyancy concept...
"A man with a new idea is a crank until he succeeds."~ M. Twain.
re: Ferrofluid
Ken...
The valvule you show is the top of all valvules I have seen and may be the solution for the old buoyance puzzle, as said by Oxygon...
The switch may be done by external power, not a big deal.
In the past I draw a little stuff like this but looking an application at artificial members for amputated people.
Good! regs. M.
The valvule you show is the top of all valvules I have seen and may be the solution for the old buoyance puzzle, as said by Oxygon...
The switch may be done by external power, not a big deal.
In the past I draw a little stuff like this but looking an application at artificial members for amputated people.
Good! regs. M.
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ken_behrendt
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re: Ferrofluid
Murilo wrote:
Below is a hypothetical flotation device that would use such a valve. But, would it work to provide the indicated perpetual motion?
Obviously, as a spherical float emerges from the top of the blob of ferrofluid, it will feel a downward pressure from the column of water above it that tries to prevent it from emerging. However, if the upward acting forces of buoyancy acting on the other floats in the tank of water were greater, then the floats should be pulled upward out of the ferrofluid and into the tank of water!
ken
Yes, if the magnetic field is strong enough and the ferrofluid is made using a silicone based liquid to suspend the magnetic particles, then this system could make a very interesting "valve" indeed.The valvule you show is the top of all valvules I have seen and may be the solution for the old buoyance puzzle, as said by Oxygon...
Below is a hypothetical flotation device that would use such a valve. But, would it work to provide the indicated perpetual motion?
Obviously, as a spherical float emerges from the top of the blob of ferrofluid, it will feel a downward pressure from the column of water above it that tries to prevent it from emerging. However, if the upward acting forces of buoyancy acting on the other floats in the tank of water were greater, then the floats should be pulled upward out of the ferrofluid and into the tank of water!
ken
- Attachments
-
- This looks workable!
On 7/6/06, I found, in any overbalanced gravity wheel with rotation rate, ω, axle to CG distance d, and CG dip angle φ, the average vertical velocity of its drive weights is downward and given by:
Vaver = -2(√2)πdωcosφ
Vaver = -2(√2)πdωcosφ
re: Ferrofluid
Yes, Ken!
Ferrofluid may suround to elements as a diaphragm or seal.
2 more points:
- a little amount of water will fall down - not a problem.
- the ferrofluid will need a kind of pulsative switch.
( I'm not sure about the need of silicone oil... )
This stuff will find some amazing applications, I'm sure!
regs. M.
Ferrofluid may suround to elements as a diaphragm or seal.
2 more points:
- a little amount of water will fall down - not a problem.
- the ferrofluid will need a kind of pulsative switch.
( I'm not sure about the need of silicone oil... )
This stuff will find some amazing applications, I'm sure!
regs. M.
re: Ferrofluid
Hi Ken,
That's a very simple and elegant design. In my opinion, I don't think it would work. I believe the viscosity of the ferrofluid, the magnetic force pulling the ferrofluid downward, and the pressure of the water on top of the ferrofluid, would not allow the hollow balls to pass through. However, it's a unique design and would certainly deserve a spot in the Hall of Fame for unworkable designs.
Here's an example of one way ferrofluid is used:
A few years ago, I worked for a company that designed and manufactured equipment for applying epitaxial coatings on silicon wafers. The epitaxial reactors we designed used an off the shelf part containing ferrofluid. This device was used to suspend and rotate a silicone carbide coated graphite susceptor, containing the wafers. The purpose of the ferrofluid was to eliminate particle contamination by reducing metal-to-metal contact and creating a seal between metal surfaces. The following link shows a rotation device similar to the one we used.
http://www.freepatentsonline.com/4630943.html
The other links at this site will give you additional information on uses for ferrofluid.
Tom
That's a very simple and elegant design. In my opinion, I don't think it would work. I believe the viscosity of the ferrofluid, the magnetic force pulling the ferrofluid downward, and the pressure of the water on top of the ferrofluid, would not allow the hollow balls to pass through. However, it's a unique design and would certainly deserve a spot in the Hall of Fame for unworkable designs.
Here's an example of one way ferrofluid is used:
A few years ago, I worked for a company that designed and manufactured equipment for applying epitaxial coatings on silicon wafers. The epitaxial reactors we designed used an off the shelf part containing ferrofluid. This device was used to suspend and rotate a silicone carbide coated graphite susceptor, containing the wafers. The purpose of the ferrofluid was to eliminate particle contamination by reducing metal-to-metal contact and creating a seal between metal surfaces. The following link shows a rotation device similar to the one we used.
http://www.freepatentsonline.com/4630943.html
The other links at this site will give you additional information on uses for ferrofluid.
Tom
"I have done so much, for so long, with so little... I can do anything with nothing." -USNMCB-4