B Can a rocket flame be controlled by a magnetic field?

[Ahmad Sadek]

An idea came to my mind after I saw the plasma reactor and how the plasma floats through a magnetic cage that prevents the nuclear reactor from melting, to make a magnetic cage that prevents the rocket engines from melting while they are working.

Is this possible, or does it take a critical mass that is not enough to put it in a rocket engine.

 

[Vanadium 50]

But rocket engines don't melt when they are working. If they did, they would stop working.

 

[Baluncore]

@Ahmad Sadek
Welcome to PF.

The rocket exhaust products would be separated into two channels by ionic polarity.
https://en.wikipedia.org/wiki/Magnetohydrodynamic_generator

If you try electric arc welding in or near strong magnetic fields, you would understand the problems associated with controlling a flame or arc using magnets.

 

[Ahmad Sadek]

But rocket engines don't melt when they are working. If they did, they would stop working.

Yes, I know that, rocket engines are cooled by hydrogen, but this requires constant maintenance when the rocket engine is reused many times.

 

[Vanadium 50]

but this requires constant maintenance

And adding magnets to the mix somehow makes this better??
I don't think this is going to solve your problem. I think you also need a more specific suggestion than "lets add some magnets" in order to have a sensible discussion. Where? How many? How strong? Where do the field lines go? What is the figure of merit to tell if this idea is working or not?

 

[Ahmad Sadek]

And adding magnets to the mix somehow makes this better??
I don't think this is going to solve your problem. I think you also need a more specific suggestion than "lets add some magnets" in order to have a sensible discussion. Where? How many? How strong? Where do the field lines go? What is the figure of merit to tell if this idea is working or not?

The magnetic field must be strong and in an appropriate form to prevent the flame coming out of the engine nozzle from melting the engine parts so that the flame comes out of the rocket exhaust without touching it so that we can restart and use the missile engines many times without the need for maintenance

 

[berkeman]

so that we can restart and use the missile engines many times without the need for maintenance

You mean kind of like these?

https://www.spaceforce.mil/Multimedia/Photos/igphoto/2002222258/

 

[Baluncore]

The magnetic field must be strong and in an appropriate form to prevent the flame coming out of the engine nozzle from melting the engine parts so that the flame comes out of the rocket exhaust without touching it so that we can restart and use the missile engines many times without the need for maintenance

Do you plan to control the positive or the negative ions in the exhaust ?

How will you keep the permanent magnets cold ?
If they reach their Curie point, they will stop working.
https://en.wikipedia.org/wiki/Curie_temperature

 

[Ahmad Sadek]

You mean kind of like these?

View attachment 318406
https://www.spaceforce.mil/Multimedia/Photos/igphoto/2002222258/

Yes, like these, but there is a difference. SpaceX is carrying out a repair process for the engines of its rockets returning from space. As for this idea presented above, it dispenses with re-repair because basically the flames do not touch the nozzle of the rocket engine, and therefore it does not need to put insulating material again and check the missile and test it many times. before re-launch

 

[Vanadium 50]

The magnetic field must be strong

How strong?

and in an appropriate form to

Which is?

prevent the flame coming out of the engine nozzle from melting the engine parts

We have this today.

flame comes out of the rocket exhaust without touching it

It's still hot. How do you think your oven (if it is a gas oven) works?

restart and use the missile engines many times without the need for maintenance

How do you know it won't need maintenance?

You don't really have an idea yet. You have some words, but nothing specific enough to have a serious discussion about.

 

[Ahmad Sadek]

Do you plan to control the positive or the negative ions in the exhaust ?

How will you keep the permanent magnets cold ?
If they reach their Curie point, they will stop working.
https://en.wikipedia.org/wiki/Curie_temperature

We can use hydrogen to cool the magnet to prevent it from losing its magnetism,

Someone may ask why the rocket engine does not cool itself with hydrogen instead of magnet cooling: The answer is that I want the rocket engine to work for long periods of time without the need to re-maintain it after each launch.

I am trying to control the flame so that it does not melt the rocket materials, I do not care in any way that I can isolate the flame coming out of the engine, but the important thing is that the method is reliable without the need for maintenance many times

 

[f95toli]

I am trying to control the flame so that it does not melt the rocket materials, I do not care in any way that I can isolate the flame coming out of the engine, but the important thing is that the method is reliable without the need for maintenance many times

Even if the flame doesn't actually reach the metal walls of the nozzle; the walls are still going to heat up due to radiative heating (the exhaust gas is very hot). It is not at all obvious that you would actually gain much; you would need to calculate how much heat is transferred via convection vs. radiation. The former will probably dominate, but keeping the magnets cold enough would also add a lot of complexity.

Also, I would be surprised of permanent magnets would work since the fields they can generate is typically quite small. Plasma containment is usually done using electromagnets and for high fields (more than a few T) you typically need superconducting magnets (this is how fusion reactors work).

 

[Ahmad Sadek]

How satrong?

Which is?

We have this today.

It's still hot. How do you think you oven (if it is a gas oven) works?

How do you know it won't need maintenance?

You don't really have an idea yet. You have some words, but nothing specific enough to have a serious discussion about.

I agree with you to some extent, but not everything you say is true.

I will introduce myself: a high school student. That is, I have not majored in physics or engineering yet, but I have been working on developing myself since I was young in technological fields, including space.

What I wanted to ask about is whether this idea can be applied in reality or not. The idea started when I thought of making a liquid rocket engine, and I had a certain difficulty in cooling the engine and I remembered how Tokamak works and how they can control a temperature of more than 100 million Kelvin without melting the materials. . And I had the idea of using this method to cool rocket engines to make them operate at high temperatures without stopping or needing to be re-maintained.

I have not yet begun the lengthy academic research on this subject, nor have I started writing a research paper on it. I started discussing the idea with my teacher, and then here on this site.

I know that I still do not have enough knowledge in this field, but I try to develop myself day after day, and there is nothing wrong with discussing these ideas here, because we can all benefit from each other's experiences, and all people learn day after day. What I try to do is build on what I learned in school and through my research, self-learning, and consulting with my teachers.

 

[berkeman]

I will introduce myself: a high school student. That is, I have not majored in physics or engineering yet, but I have been working on developing myself since I was young in technological fields, including space.

What I wanted to ask about is whether this idea can be applied in reality or not.

Have you read the Wikipedia article yet? The References may also provide you some interesting reading:

https://en.wikipedia.org/wiki/Magnetic_nozzle

 

[256bits]

What I wanted to ask about is whether this idea can be applied in reality or not. The idea started when I thought of making a liquid rocket engine, and I had a certain difficulty in cooling the engine and I remembered how Tokamak works and how they can control a temperature of more than 100 million Kelvin without melting the materials. . And I had the idea of using this method to cool rocket engines to make them operate at high temperatures without stopping or needing to be re-maintained.

You can start here with your research
http://plasma.kulgun.net/sol_page/

A Tokamak is just a solenoid turned into itself.

A solenoid confines the plasma in the radial direction, but lets the plasma exit(enter) from the ends, which is what you want. You would have to calculate the field intensity needed to maintain the plasma away from the walls based on the mass flow rate of the plasma. To low a field and the some plasma will touch the walls; too high and the plasma may pinch to a small jet negating the effect of the rocket nozzle shape. The plasma follows the field lines as it passes through the nozzle.

It is a simple concept that you could experiment with by the use of a burning flame such as that from a propane torch, extending the torch length with a glass tube ( or hard plastic ) to see through, wrapping some turns of wire around the tube, pass a current through the turns to create the internal magnetic field, and see what happens.

 

[Vanadium 50]

Have you read the Wikipedia article yet?

That's a somewhat different problem. That's for something more like a VASIMIR drive: electric, high impulse, low thrust. Just the opposite of a rocket.

 

[berkeman]

That's a somewhat different problem. That's for something more like a VASIMIR drive: electric, high impulse, low thrust. Just the opposite of a rocket.

Agreed, but I thought it might be helpful for the OP in visualizing magnetic field lines, and seeing some of the limitations.

 

[Bystander]

would need to calculate how much heat is transferred via convection vs. radiation.

500 K is the upper limit for significant contributions from conduction/convection; beyond that it's essentially radiation/ive heat transfer. https://en.wikipedia.org/wiki/Stefan–Boltzmann_law

 

[Ahmad Sadek]

You can start here with your research
http://plasma.kulgun.net/sol_page/

A Tokamak is just a solenoid turned into itself.

A solenoid confines the plasma in the radial direction, but lets the plasma exit(enter) from the ends, which is what you want. You would have to calculate the field intensity needed to maintain the plasma away from the walls based on the mass flow rate of the plasma. To low a field and the some plasma will touch the walls; too high and the plasma may pinch to a small jet negating the effect of the rocket nozzle shape. The plasma follows the field lines as it passes through the nozzle.

It is a simple concept that you could experiment with by the use of a burning flame such as that from a propane torch, extending the torch length with a glass tube ( or hard plastic ) to see through, wrapping some turns of wire around the tube, pass a current through the turns to create the internal magnetic field, and see what happens.

Well, suppose the outside flame is just a candle flame. What I read here: https://www.researchgate.net/publication/335465123_Effect_Of_Electromagnetic_Field_On_Combustion_Of_Candle_Flame

magnetic field increases oxygen concentration. Because of the oxygen is paramagnetic material. the magnetic field increases the oxygen concentration around the candle flame and the magnetic field enhances the buoyancy force of the candle flame.

Do you think I can control the flame by the magnetic field or will it increase the ignition of the materials around it?

 

[256bits]

Well, suppose the outside flame is just a candle flame. What I read here: https://www.researchgate.net/publication/335465123_Effect_Of_Electromagnetic_Field_On_Combustion_Of_Candle_Flame

magnetic field increases oxygen concentration. Because of the oxygen is paramagnetic material. the magnetic field increases the oxygen concentration around the candle flame and the magnetic field enhances the buoyancy force of the candle flame.

Do you think I can control the flame by the magnetic field or will it increase the ignition of the materials around it?

I thought you were asking about the control of the hot plasma gases going out the nozzle of a rocket and not of the actual combustion of the fuel and oxidizer.
https://cfdflowengineering.com/rocket-engine-combustion/

The citation might not be what you are after, and indeed there is not much there other than a reporting that a magnetic field has an effect upon diffusion combustion. The magnetic field lines from this concept are probably not what you are after.

the candle thing, I suspect, has more do with, but not as in such a direct fashion, as from the link,

The rocket exhaust products would be separated into two channels by ionic polarity.

from post #3, but difficult to tell as they don't tell much in depth about the setup.

Please go back to post #10

You don't really have an idea yet. You have some words, but nothing specific enough to have a serious discussion about.

Be focused, do more reading, and research.
It actually is your concept and it cannot be done in a day.
( Note : You mentioned the tokomak - so to add to that --> the fission fusion concept, or rather plasma confinement, is getting on to be 100 years old soonish and yet there is no sustainable fission fusion technology to this day. A simple idea - a torus within a magnetic field can contain a plasma. From that simple idea, and continuing to 'push the envelope' to achieve the desired high temperatures, little nasty problems were overcome by doing this and that with added magnetic fields, and today we have the giant systems based on the simple Tokamac .

Your concept may or not plan out the same way, but you do have to have a plan to narrow down, rather than grasping. Grasping shows that you are in the initial concept phase of what may or may not work, and that in and of itself is how all things do start off, so not a bad thing. )

 

[Vanadium 50]

magnetic field increases oxygen concentration. Because of the oxygen is paramagnetic

Baloney,. If you want to be taken seriously here, it is best not to post nonsense.

Oxygen is paramagentic, sure. It's magnetis susceptibility is much, much less than iron or steel. Like 0.000000000001 times as big. (I don't use scientific notation in order to emphasize this) If your position is "gosh, I'm just a kid, I don't know any of this", I would suggest that you wait until you do to start lecturing us on magnetism and the magnetic properties of materials.

If nothing else, the absence of warning labels of magnets "Danger! May suck all the oxygen out of a room!" should have told you something.

If you want to learn, ask questions. Don't make a parade of false statements hoping to be corrected. That's inefficient, and will just make people mad.

 

[nasu]

( Note : You mentioned the tokomak - so to add to that --> the fission concept, or rather plasma confinement, is getting on to be 100 years old soonish and yet there is no sustainable fission technology to this day. A simple idea - a torus within a magnetic field can contain a plasma. From that simple idea, and continuing to 'push the envelope' to achieve the desired high temperatures, little nasty problems were overcome by doing this and that with added magnetic fields, and today we have the giant systems based on the simple Tokamac .

It should be fusion. Fission has nothing to do with it. It is used in nuclear power plants.

 

[256bits]

It should be fusion. Fission has nothing to do with it. It is used in nuclear power plants.

Silly mistake. Corrected, Thanks.

 

[Ahmad Sadek]

If you want to learn, ask questions. Don't make a parade of false statements hoping to be corrected. That's inefficient, and will just make people mad.

One moment, please.
Can you read the main question in this subtraction again ?

"Can a rocket flame be controlled by a magnetic field?"

It seems that I started with a question in order to learn, as you told me, is this true???!

I am not presenting false statements as you claimed. I am just presenting an idea to discuss here, not false allegations or etc. I have said this previously, but you do not understand what I wanted from my question yet

What I wanted to ask about is whether this idea can be applied in reality or not. .

I started with a question, not a physical hypothesis. I am just trying to present the idea to be discussed, not because I want to prove it without clear evidence. Do you understand the purpose of this proposition? It is only a question for discussion only...

 

[Vanadium 50]

Are you sure "Before I started with all the baloney i posted a question, so I should be allowed to post as much nonsense as I want" is the position you want to take?

You made a statement. That statement was wrong by a factor of a trillion. You might not want to spend the rest of the thread defending it.

 

[Ahmad Sadek]

"Before I started with all the baloney i posted a question, so I should be allowed to post as much nonsense as I want" is the position you want to take?

Can you explain why you are upset because I asked a question?

No, I'm just asking to learn. The idea came to my mind, so I wanted to discuss it in this forum.

Why do you think that forums were not made to discuss ideas and ask questions? It seems that it is difficult for you to understand that I am merely presenting an idea here for the scientific debate as to whether it is applicable or not.

In any case, I will stop the intellectual discussion with you, because this discussion has begun to become what is called "sterile discussion."

If you have a proposal to support or refute this idea regarding controlling plasma or flames for rocket, you are welcome.

I hope you understand what I am trying to convey. Thank you.

 

[PeterDonis]

@Ahmad Sadek the simplest answer to your question is that, if you want to know why rocket engineers at SpaceX or other places are not using magnetic fields in the way you suggest, you would need to ask them. They are the ones who are intimately familiar with all of the engineering requirements for rocketry and all of the difficult tradeoffs that need to be made. It is easy to speculate, but speculation unconstrained by a detailed knowledge of the experimental facts is highly unlikely to lead anywhere useful.

That said, I can think of several general reasons why the sort of scheme you are asking about would not be workable for a rocket:

(1) Confining a plasma with magnetic fields is very hard. Nuclear fusion physicists have been working on that for more than half a century, and the main thing they have found out is that even the best confinement schemes they have come up with so far aren't good enough--the plasma still leaks out and hits the walls of the reactor and spoils things.

(2) Generating the strong magnetic fields that are required takes heavy, superconducting magnets, far too massive to be feasible for rockets.

(3) Strong, superconducting magnets require maintenance too--quite likely even more than existing rocket engines.

Ultimately, questions like this are not resolved by arguments on Internet forums. They are resolved by looking at whether anyone actually succeeds at implementing the suggestion.

 

[PeterDonis]

I am merely presenting an idea here for the scientific debate as to whether it is applicable or not.

The answer to this, as I pointed out in post #28, is that this idea is not amenable to scientific debate. The way to test your idea would be for someone to actually try it. That's way outside the scope of PhysicsForums. We are here to help people understand mainstream physics, not to tackle difficult engineering problems--the latter is what companies like SpaceX are for.

 

[PeterDonis]

Since the OP question is not really suitable for PF discussion, this thread is now closed.