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I am doing my final year engineering project on Magnetic Field Assisted Combustion and was curious to see what people thought about it.

Companies sell rare earth magnetic arrangements to be attached to fuel lines of gas burners and they are said to improve combustion efficiency but why exactly?

I have performed a number of experiments using a standard butane/propane gas burner with some magnets manufactured by one of said companies and have had some contradicting results. With lower strength magnets, heat transfer unexpectedly slowed down but with a much stronger arrangement, heat transfer rate was increased.

Also, the burn out time of the same amount of gas took 8 minutes less with the magnets in place around the fuel line.

I have read a number of journals on similar subjects but even within these, the actual reason for the increase in heat output is still not known.

Any thoughts on the subject would be massively appreciated and possibly give me some other areas to investigate that I have not already thought of.

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    $\begingroup$ Some details on the methods and results of your experiments would be helpful here. Particularly way that you measured flow and heat transfer. Links to the journal articles would be great. $\endgroup$
    – user3823992
    Apr 4, 2015 at 1:28
  • $\begingroup$ It was just a simple heat transfer experiment, heating 250g of water with a standard gas burner. I took incremental temperature readings every 30 seconds and took the weight of the canister before and after. Without any magnets, heating water to 95 degrees took around 2 minutes, with the magnets it took varying times from around 1min 50 to 2min 10. I also noticed it seemed to take less time when the burner was left to go cold before heating again. $\endgroup$
    – James Dawson
    Apr 4, 2015 at 13:18
  • $\begingroup$ And the journals aren't available online I don't think. They were on the effect of magnetic fields on diffusion flames under microgravity conditions. As the magnets were positioned around the flame I don't believe it would have the same effect when placed on the fuel line. $\endgroup$
    – James Dawson
    Apr 4, 2015 at 14:10
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    $\begingroup$ I'm actually familiar with some of that work magnetic effects on flames (by Fujita et al.). That's the result of paramagnetic forces on oxygen. It's not really changing the chemistry, but it does perturb the flow a bit. The effect is weak and requires very strong field gradients at the flame to be noticeable under normal gravity. $\endgroup$
    – user3823992
    Apr 4, 2015 at 14:24
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    $\begingroup$ If you're referring to your experiments. I'm honestly not that convinced. There's no physical mechanism by which the fuel flow in the lines would be altered by the magnets. The variations that you've observed are more likely the result of other factors (e.g. initial burner temp, amount of gas left in tank, order of the experiments). (not trying to be snarky here, just trying to help) $\endgroup$
    – user3823992
    Apr 4, 2015 at 15:09

4 Answers 4

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The Zeeman effect describes the interaction between the magnetic field and atoms. It lowers or rises the energy level of each atomic state, in your case molecular state. It`s impossible to ionize a gas with magnetic field, since this would mean that that the magnetic field had done work to the system. My guess is that the magnetic field had lowered the ionization potential.

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  • $\begingroup$ That's at relatively low velocities and field strengths. With very high velocities and magnetic fields you get Lorentz ionization (in effect at super fast velocities and fields the effect is all about the Lorentz electric field in the restframe of the atom which can cause ionization). And I think your thermo analysis only tells us that in equilibrium ionization rate must equal recombination rate (the energy is coming from the KE of the molecules). See: aanda.org/articles/aa/full_html/2020/03/aa37413-19/… and many other papers on google about pop effect of mag field $\endgroup$
    – Peter Gerdes
    Apr 23, 2023 at 0:53
  • $\begingroup$ Though obviously your answer is the one appropriate to this context. I'm giving the answer that applies when high energy gases interact with magnetars and the like. (The ionization just converts the KE of the parts of the electron/nucleas into PE as they seperate). $\endgroup$
    – Peter Gerdes
    Apr 23, 2023 at 0:56
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I don't know about ionizing gas but I do know about magnetophoresis. Oxygen is paramagnetic so oxygen concentrations should be higher around magnets than in ordinary air. This could make it easier for fuels to combust.

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Reading the original question a posible mechanism has suggested itself to me. As the gas travels along the pipe "streaming currents" can be generated by friction. This is a phenomenon in the literature where by electrostatic charge can build up on the pipe and there is a concentration of charged particles in the boundary layer. One consequence has been instances of fuel fires when Kerosene is delivered through a hose to refuel an aircraft. The combination of such a steaming current plus a magnetic field could induce forces on the fuel maybe encouraging transition and turbulence.

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i would say yes. magnetic field does ionize the gas. "Ionization is the process by which an atom or a molecule acquires a negative or positive charge by gaining or losing electrons". and this as a topic already. Can I produce radio waves by waving my hand? therefore the gas MOVING through a magnetic field would accumulate a charge.

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