Do Magnets Affect Fire Behavior?

[zynan]

I was told by my teacher that fire is plasma and that plasma can be controlled by magnets. Does that mean it is possible to effectively use magnets to control fire?

 

[negitron]

No. Even in fires which are hot enough to produce plasmas, the flames are essentially neutrally charged--although the electrons are separated from their nucleii, they are still more or less homogeneously mixed with them, so the net charge is zero. Only plasmas which have had their charges separated (such as by an electric field, as in a plasma TV) can be affected by electric or magnetic fields on a macroscopic scale.

 

[maverick_starstrider]

That's not true. Electric and magnetic fields will induce dipoles in a plasma just as they do in a neutral solid (but to an even greater degree). However, the net effect of dipole interactions, I imagine, would do significantly less to control the path of the flame then the fuel aspect (i.e. it will spread to areas rich in oxygen and fuel).

 

[nnnm4]

I suppose if you got a really strong magnet, you could attract oxygen and control which direction the fire burned in. That has nothing to do with it being plasma though.

 

[berkeman]

Okay folks, the next post better have some pointers to some peer-reviewed journal articles on this, or the responses will be deleted as unsubstantiated claims. It shouldn't be that hard to look up...

 

[negitron]

Okay folks, the next post better have some pointers to some peer-reviewed journal articles on this, or the responses will be deleted as unsubstantiated claims. It shouldn't be that hard to look up...

Well, it looks as though I'll have to partially retract my earlier post, at least for the case of very strong B fields:

http://ieeexplore.ieee.org/Xplore/l...065242.pdf?arnumber=1065242&authDecision=-203

Note, however, that it appears to be the oxygen that is affected by the B field, rather than the flame itself.

 

[nnnm4]

Yeah, that's what I was saying. Oxygen is paramagnetic.

 

[maverick_starstrider]

It should be noted that in a 2 Tesla magnetic field you'd be ripping nails out of walls and such and would require a giant superconducting magnet (MRI's are around 3 Tesla). Which makes it pretty useless for any form of 'fire fighting'

 

[ghoshg]

Great idea ! controlling fire by a magnet ! First of all, I would like to know whether fire should be considered as 'plasma phase' of matter ?

 

[negitron]

I would like to know whether fire should be considered as 'plasma phase' of matter ?

Nearly all ordinary fires aren't hot enough to be plasmas. What you see as flame is simply ordinary gas heated to incandescence.

 

[Borek]

Flame is conductive and as such will be reacting to magnetic fields - that's what magnetohydrodynamics is about. How strong the interaction will be is completely different question - but it looks to me like it is so weak that we are outside of the realm of practical applications.

 

[DJDAudio]

I signed up just to post my results to the questions above,

Some time back I was trying to make my own solar flares in the lab.

https://fbcdn-sphotos-a.akamaihd.net/hphotos-ak-snc6/198578_10150137123923291_519458290_6399092_828389_n.jpg

https://fbcdn-sphotos-a.akamaihd.net/hphotos-ak-snc6/200686_10150137123883291_519458290_6399090_6825074_n.jpg

Those are pictures I took from my tests with Fire and very large high voltage fields.

In this experiment I have a 15,000 Watt X ray transformer running at 50KV DC through the fire to the ring of the burner as ground.

I was able to manipulate the shape of the fire by changing the voltage and current characteristics.

So this is an interesting result, What do you all think is going on?

Happy to answer any questions about my rig.

 

[DJDAudio]

Also the gas used for the experiment was Propane

 

[Drakkith]

In this experiment I have a 15,000 Watt X ray transformer running at 50KV DC through the fire to the ring of the burner as ground.

I was able to manipulate the shape of the fire by changing the voltage and current characteristics.

So this is an interesting result, What do you all think is going on?

Happy to answer any questions about my rig.

I'd say you were ionizing the air and fire due to the 50,000 volts.

 

[jetwaterluffy]

This whole "is fire plasma" thing turns up repeatedly. I think a thread stickyed on it would be useful.

 

[Vanadium 50]

The only practical way to control fire with magnets is that if you can pour enough magnets on a fire, eventually you will snuff it out.

 

[cmb]

I was able to manipulate the shape of the fire by changing the voltage and current characteristics.

I think it would be interesting if you can post a better write-up of the test, kit layout, controls, images with flow rates (albeit arbitrary units like 'angle of valve setting', if you aren't using a mass flow device), &c.. Also more info on your power supply and how you come to conclude you have a 50kV discharge. Are we looking at a PSU pulled down to quite low volts with a 'high' current, or otherwise how does the presence of the flame affect the conductance/arcing in that region.

The second image does look interesting, but not enough 'control' information here to begin making second guesses at what we are looking at.

 

[DJDAudio]

I'd say you were ionizing the air and fire due to the 50,000 volts.

Bingo, that is what I was thinking as well. You can even hear it slightly.

As for an experiment, I set up the rig again last night and this time I went with a large coil mounted fixed with a deflection shield, I then ran 10KV DC to a cap bank, and sent an Directed EMP at the flame, and sure enough it would 'poof' on impact. like explained above, it was not a huge effect but noticeable.

Also interesting effect, while the caps where charging the fire would 'list' or slightly lean as if attracted to the coil, then on fire, it would move abruptly in the opposite direction.

I would love to test this in a vacuum, the only problem is getting fire to burn with no oxygen :P

 

[DJDAudio]

I think it would be interesting if you can post a better write-up of the test, kit layout, controls, images with flow rates (albeit arbitrary units like 'angle of valve setting', if you aren't using a mass flow device), &c.. Also more info on your power supply and how you come to conclude you have a 50kV discharge. Are we looking at a PSU pulled down to quite low volts with a 'high' current, or otherwise how does the presence of the flame affect the conductance/arcing in that region.

The second image does look interesting, but not enough 'control' information here to begin making second guesses at what we are looking at.

You got it! Let me work on a sketch,

As for my power supply,

It is a 15,000 Watt X-Ray transformer. The above pic is with it removed from the oil. the full wave bridge is on the left side.

The output voltage was first calculated by the arc distance I was getting consistent arcing at 0.787" so for AC that is about 47KV being that I was using DC my best guess was 50KV

I then grabbed my High voltage probe,
Mine looks just like this,

And verified my output.

Now with the fire on, all bets are off, for it shortened the arc distance as well as introduced a dynamic load.


the fire was being fed from a large Lab bunsen burner, similar to this,

And was fed an constant stream of propane. As for the flow, I was not worried about this, for all I needed was a consistent height flame for the tests.


and for my EMP tests last night I used my Glassman,

I have much more consistent control over current and voltage.




Now you asked about control, I can not bend the fire and hold it there, the pictures abaove where after many takes to get right, the effect is pulsed, for once the fire conducts the full force of the current it deflects drops the connection and repeats,

so the effect is a fast oscillating almost chaotic experience. I did find through pictures I was able to effect the shape of the fire for only milliseconds at a time. for the reasons stated above.

When I get some free time, I will try to recreate my original setup and get some video to explain as well

 

[DJDAudio]

Also I will mention the 15,000Watt X-Ray transformer I had to current limit to 600Watts for the test, for at full power, the fire ball that was formed at full flame deflection got to be many feet in length!

 

[DJDAudio]

And here is a picture of the Power supply I built to control the X-Ray transformer.

http://www.djdlabs.com/GALLERY/var/resizes/Powe-Box-Update-%236/_DSC0028.jpg?m=1322346647

 

[Edgardo]

- In this textbook (page 468) they describe how a combustion flame changes in a magnetic field.

- This here describes how neodymium magnets deflect a candle flame. (Though I am a little concerned if this actually happens: video of a spoon "pushing" a flame)

 

[DJDAudio]

This was a one in a million shot, this is at the exact moment the arc conducts through the flame and the huge current inrush throws the flame violently, so much in fact, you can still see the electric arc that is going to nothing on the left side.

https://fbcdn-sphotos-a.akamaihd.net/hphotos-ak-snc6/190506_10150137124513291_519458290_6399114_2184682_n.jpg

 

[DJDAudio]

- In this textbook (page 468) they describe how a combustion flame changes in a magnetic field.

- This here describes how neodymium magnets deflect a candle flame. (Though I am a little concerned if this actually happens: video of a spoon "pushing" a flame)

The spoon one ( this is just a hunch ) is accurate, but for different reasons, there is a large air flow around the flame from the different air density so when the spoon is introduced a slight laminar flow is introduced and a smooth inrush of cool air air allowed to stream up and into the flame, this boosts the flame height as well as allows the flame to follow with or bend in the new air current.

 

[DJDAudio]

I see allot of people talking about how the Oxygen is the effected medium in the experiments,

I have a 99.99% Oxygen generator that will generate 5L/m of oxygen, I will try to recreate my experiment but this time change the oxygen concentration to see if indeed there is any change in the effect, if it holds true I should see more of a deflection in the flame.

 

[truman]

This was a one in a million shot, this is at the exact moment the arc conducts through the flame and the huge current inrush throws the flame violently, so much in fact, you can still see the electric arc that is going to nothing on the left side.

https://fbcdn-sphotos-a.akamaihd.net/hphotos-ak-snc6/190506_10150137124513291_519458290_6399114_2184682_n.jpg

How much of this effect can be accounted for by rapidly heated air expanding around the arc and disrupting the flame?

 

[DJDAudio]

How much of this effect can be accounted for by rapidly heated air expanding around the arc and disrupting the flame?

the arc is only about 600watts so the heat generated would be miniscule in comparison to that of the flame. So I would say it has minimal effect.

https://fbcdn-sphotos-a.akamaihd.net/hphotos-ak-snc6/199216_10150137124548291_519458290_6399116_960353_n.jpg

But the Fire does have an effect on the arc interestingly enough.

 

[cmb]

Also interesting effect, while the caps where charging the fire would 'list' or slightly lean as if attracted to the coil, then on fire, it would move abruptly in the opposite direction.

This is a known effect. Flames are distorted in the presence of an electric field. A colleague mentioned some years ago that the effect had been used to actually measure electric field strength, when other methods were less suitable. (I am not sure if that was his own creative idea, or whether it had actually been done.)

Not sure what you'd see in a vacuum - the plasma would fill the vacuum chamber, whereas here you have a distinct plasma edge where ionisation/recombination drops to negligible levels.

 

[Edgardo]

Here are some videos of flames in presence of an electric field:
1. Corona Wind Electric Flames
2. Corona Wind Effect
3. High Voltage Corona Wind
4. Singing Candle

 

[bbbeard]

No. Even in fires which are hot enough to produce plasmas, the flames are essentially neutrally charged--although the electrons are separated from their nucleii, they are still more or less homogeneously mixed with them, so the net charge is zero. Only plasmas which have had their charges separated (such as by an electric field, as in a plasma TV) can be affected by electric or magnetic fields on a macroscopic scale.

Are you under the impression that wire coils with charge flowing through them have a net charge? I think you are confusing "charge" with "current".

FWIW I did a science project in high school in which I showed that a magnetic field significantly affected the resistance of a Bunsen burner flame. Extra credit if you can predict whether the resistance went up, or down, when the magnetic field was turned on, and explain why. However, I did not try to measure the flame shape with and without the magnetic field.

BBB

 

[cjameshuff]

To some degree, yes, magnets can control (or at least influence) fire. Flames are generally at least partially ionized (and various salts will ionize in flames, which is how the old "flame test" and colored fireworks work), and a net charge is not required, only a conductive fluid (saltwater can be manipulated electromagnetically too, and the plasma in fusion reactors like tokamaks is pretty neutral overall).

The same basic effects can even be used to directly produce electrical power...MHD generators are an area of active research and power plants using the technology have been built and operated. The focus there is in converting motion of combusting gases to electrical power, though, not in doing any particularly complex control via magnetic fields.

 

[Teiwaz]

Ok so i took over 30 matches to run a test, i placed two magnets on either side of a standard box wood match, near the base of the match facing one another , The match was held with a stationary tweezer like structure, and when the fire reached the area of the magnet it died out or in some cases, reversed the flame direction. I also did a few tests where the matches did not have magnets, in which case the entire match in all cases were consumed. What this means i do not know.. but i found it interesting.. I assumed because the magnet might be a conductor there could have been a possibility of heat transfer... but wasnt sure. either that or the magnets actually did stop the flame from burning the entire match in which case I am interested to find out what that means...

oh and i took four magnets and placed them on the match and noticed i could actually box in the flame well, until the wood inbetween the magnets was no longer able to burn.

 

[cjameshuff]

Ok so i took over 30 matches to run a test, i placed two magnets on either side of a standard box wood match, near the base of the match facing one another ,

This is unlikely to show any effect due to the magnetic field, anything you see is likely just due to the cold, air-obstructing magnets. The flame isn't substantially magnetic like iron is, it needs to be moving through the magnetic field or carrying an electrical current, or the magnetic field needs to be changing rapidly so it induces a current in the flame.

 

[rprosser]

Ok so i took over 30 matches to run a test, i placed two magnets on either side of a standard box wood match, near the base of the match facing one another , The match was held with a stationary tweezer like structure, and when the fire reached the area of the magnet it died out or in some cases, reversed the flame direction. I also did a few tests where the matches did not have magnets, in which case the entire match in all cases were consumed. What this means i do not know.. but i found it interesting.. I assumed because the magnet might be a conductor there could have been a possibility of heat transfer... but wasnt sure. either that or the magnets actually did stop the flame from burning the entire match in which case I am interested to find out what that means...

oh and i took four magnets and placed them on the match and noticed i could actually box in the flame well, until the wood inbetween the magnets was no longer able to burn.

You may wish to see my post, as I managed to extinguish a match flame via a collapsing magnetic field quite easily. I wish that more people would do experiments of this nature rather than just relying on their theoretical knowledge, which clearly can be quite limited in some cases. Unfortunately I do not have the resources to do much myself at present.

Richard