Electromagnetic Technology in Jet Engines

New and old developments in aviation technology.
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Kryptid

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Unread post01 Mar 2009, 00:44

Another idea. This time it's partly mine and partly inspired by someone else on the Halfbakery:

http://www.halfbakery.com/idea/Electrostatic_20Gas_20Turbine#1079542800

In a nutshell, it's a jet engine that has no mechanical fans, compressors or turbines, but uses electromagnetic fields to move ionized air. In order to simplify referring to this design, I'll call it the "electroramjet". I've decided to investigate this further. I've attached a set of figures to illustrate the concepts.

Figure 1: This is a schematic of a standard turbojet engine. "A" represents the low-pressure compressor array, "B" is the high-pressure compressor array, "C" is the combustion chamber with fuel injectors, "D" is the high-pressure turbine stage, "E" is the low-pressure turbine stage, and "F" is the engine nozzle. This should be fairly obvious to a lot of you.

Figure 2: Here is the electroramjet's schematic. The very first stage is the ionizer "A". This stage uses electrical energy to ionize the air that enters the engine intake. This stage could take several forms. One possibility is to use an electrified mesh (Figure 3), an electrical arc generator (Figure 4), or an ionizing radiation generator (Figure 5). I don't know which of these three ionizers would represent the best compromise between ionizing efficiency, drag, cost, safety and weight, but I would like to hear from you which you think would be.

The second part is the low-pressure compressor stage "B". It does not use a spinning array of compressor blades. Instead, it uses a series of pulsing electromagnetics to compress and pull the newly-ionized air further into the engine. This relies on the fact that electric and magnetic fields can push and pull electrically charged fluids. The third stage is the high-pressure compressor stage "C". It works the same way as the previous stage, but would have some kind of modification to its power supply, pulse rate, field strength, etc. in order to allow it to better emulate the high-pressure compressor stage of a standard jet engine.

The fourth part is pretty much the same as in a normal jet engine. Compressed air is fed into the combustion chamber "D" where fuel is mixed with it and ignited. I don't know if fuel combustion in ionized air would differ much from neutral air or not, but this could be an important factor in the electroramjet's performance. The hot, expanding air is forced through the high-pressure turbine stage "E", where the fast-moving, ionized air would cause electromagnetic generators in the engine wall to produce power thanks to the inherit electric field in the ionize air. This would be similar to certain wind turbines which use ionized wind to generate power without the use of giant propellors.

The energy generated by the high-pressure turbine stage would be sent through wires to power the high-pressure compressor stage "C". Likewise, the low-pressure turbine stage "F" would generate energy to power the low-pressure compressor stage "B". Either the nozzle "G" or the central shaft could be used to neutralize the ionized air to return it to its non-ionized state. The energy generated by the neutralization of air could be used to help power the ionizer stage (since ionizing air requires energy, then neutralizing it must release energy). I don't expect it to 100% efficient, of course, so another source of power would have to supply the ionizer stage in addition to the deionizer.

So in effect, the more the turbine section generates power, the more the compressor stage can compress and pull air, which mean more thrust, which means more turbine power, and so-on and so-on. I think this is kind of how a normal jet engine works, right (the turbine stage powers the compressor stage, I mean)? I know it can't just keep going up. There will be temperature and compressibility limits to thrust generation.

Efficiency is a concern for me. In a normal turbojet, any air molecules in the way of the spinning compressor blades will be moved. In an electroramjet, however, the only molecules that can be moved directly by the electromagnetic compressor stage would be those that are ionized. It's probably not practical to ionize every single air molecule that enters the intake, so you would get less air movement for every given watt of power the compressor array consumes in an electroramjet than in a turbojet.

Also, electrical heat loss is a concern. As the thrust goes higher and higher, the amount of electrical energy generated by the turbine stage to be sent to compressor stage would go higher as well. It might be that the wires could get so hot that they would melt or start fires. Besides, the heat loss would mean another loss in efficiency. Room temperature superconductors, if ever developed, may go a long way to helping alleviate this problem.

Magnets operating at high temperatures may also be needed (if at all possible). Otherwise, a lot of cooling technology may be needed.

On the other hand, there would be several advantages to this design. Since there are no compressor or turbine blades to melt, the speeds at which the electroramjet can operate could potentially be higher than in a regular turbojet or turbofan. At sufficiently high speeds, you could actually turn all of the electromagnets off and let the engine operate as a standard ramjet. Thus, you have a ramjet that can operate at zero speed thanks to the electromagnet systems which keep it working at low speeds.

Also, since there are no blades to break off due to bird strikes or metal fatigue, the engine could also be less prone to FOD and DOD.

Any and all criticisms are welcome.

Another section of this thread, regarding electromagnetic engine nozzles and thrust-vectoring, will be added later.
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Guysmiley

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Unread post01 Mar 2009, 07:36

Interesting thought, but I don't know how you could compress ionized air anywhere nearly as efficiently as an mechanical axial compressor. Air is a pretty serious insulator. You'd need a lot of current and a LOT of voltage.

The one part that really jumps out at me is:

This would be similar to certain wind turbines which use ionized wind to generate power without the use of giant propellors.


Never heard of such a beast. Has anything ever been built using such a concept, or does it exist solely in Wikipedia?
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Unread post01 Mar 2009, 14:15

I doubt an "electroramjet" would be practical. Where are you going to get all your electricity to power your engine? Nuclear? I’m a fan of nuclear electrical power in some applications such as some land-based nuclear power plants, submarines and aircraft carriers; however I think the idea of an aircraft with a nuclear power plant is a very risky and dangerous proposal. I don’t think you could get enough electricity from solar; perhaps if it was extremely high altitude that the aircraft is essentially in low orbit and just needed enough thrust to prevent decay.

I really don’t think your idea is an entirely new one; it seems to be a morph of existing technology like ion propulsion and the jet engine.

Hall effect thruster
http://en.wikipedia.org/wiki/Hall_effect_thruster

I vaguely seem to remember some similar proposals and/or prototypes. I think it was mainly proposed for very high altitude and very high-speed scramjets. I think it was horribly inefficient; but one of the very few ways that a jet engine could work at extremely high speeds. I think the reason it was proposed is at extremely high speeds it’s hard to get normal combustion to propagate fast enough to produce usable thrust in a scramjet (at extremely high speeds). Often exotic fuels (like hydrogen) and or very long engines are needed to support combustion. I think Ion/microwave/beam generators were proposed to mimic combustion So that even higher speeds could be achieved and that shorter engines could be used.

I think the name of that site is appropriate “halfbakery” there seems to be a lot of junk science and pseudoscience and a lot of outlandish ideas. However despite my criticism; I think it may have some positive influence on the scientific community. Sometimes it takes some out-of-the-box thinking and willing to consider what seems to be outlandish to make breakthroughs in science. Many scientists that contributed the most were often considered crackpots; however sometimes scientists have the last laugh, though sometimes it may be posthumously.

Many of the authors seem to be trying to play the Star Trek game; where they popularize science with science fiction; and then they erroneously try to take credit for it. IE ion propulsion was conceived and prototyped and tested long before Star Trek was ever written; yet many try to attribute the science to Star Trek.

Many of the authors seem to be con man and shills trying to create a lot of hype/buzz for their own financial greed and/or to advance a political agenda. Some of them seem to be using pseudoscience psychobabble to try to make the Shangri-La of green energy appear more doable/practical than it really is; to advance the global warming hysteria that is wrecking our economies and driving us toward socialism and bankruptcy.

I’m finding junk science/pseudoscience becoming more popular as the scientific community becomes more fascist. More and more I’m finding that the scientific community isn’t practicing real science. I find more and more that are learning institutions of science are advancing a political agenda which is corrupting the scientific community. I find more and more that these political agendas are advanced by only offering grants or continuing grants to “scientists” that use pseudoscience/junk science to advance a politically correct agenda.


Perhaps it's my reading comprehension. Perhaps many of these authors are as bad writers/grammar or worse than me; however I can’t help but feel that some of them really don’t seem to understand the science they are trying to talk about.

The movement of charge then creates electricity by Lenz' Law (remember that "right-hand rule" from science class?)

http://www.halfbakery.com/idea/Vane-les ... _20Turbine
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LordOfBunnies

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Unread post01 Mar 2009, 20:08

Sorry man, no dice. The principal has been tried in much larger, more controlled environments than a jet engine and failed miserably. The problem is not that the theory doesn't work, it's that putting it into practice is impossible.

Look up Arcjet wind tunnels (thank you hypersonics class, finally useful). They were all the rage in I believe the 80's. There's actually a really cool one over in Europe that uses a waterfall to spin a HUGE flywheel. They arrest the flywheel very quickly and use the power from that to power the hypersonic wind tunnel. The main problem with anything arcjet related is that it is impossible to get consistent heating around the tube. So you'll end up with hot spots, cold spots, massive gradients. It's just not a very pretty picture. A LOT of scientists worked their butts off to try to make them good, but they couldn't get the flow field consistent so they were subsequently abandoned. Think about it this way. You've got a very hot line flashing across the center of the tube and that has to spread out to make everything consistent but the mixing distance to do that is way longer than anything feasible.

Anyway, this is a ramjet application so you'd have to generate the electricity somehow and you're starting supersonic. So in the end you're burning fuel in an inefficient device to generate power for another inefficient device so by the time you're done you get less use of the fuel you'd be burning to get the power in the first place. It's another, interesting idea that'll never work.
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Kryptid

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Unread post03 Mar 2009, 08:00

Never heard of such a beast. Has anything ever been built using such a concept, or does it exist solely in Wikipedia?

Unfortunately, I've got nothing for you. I just heard on that Halfbakery page that the idea for electric wind turbines was "already baked". I don't know much more than that.

Look up Arcjet wind tunnels (thank you hypersonics class, finally useful). They were all the rage in I believe the 80's. There's actually a really cool one over in Europe that uses a waterfall to spin a HUGE flywheel. They arrest the flywheel very quickly and use the power from that to power the hypersonic wind tunnel. The main problem with anything arcjet related is that it is impossible to get consistent heating around the tube. So you'll end up with hot spots, cold spots, massive gradients. It's just not a very pretty picture. A LOT of scientists worked their butts off to try to make them good, but they couldn't get the flow field consistent so they were subsequently abandoned. Think about it this way. You've got a very hot line flashing across the center of the tube and that has to spread out to make everything consistent but the mixing distance to do that is way longer than anything feasible.

That would apply to the electrical arc version of the ionization stage, right? What about the electrified grid or the ionizing radiation options? Would those fare better?

Anyway, this is a ramjet application so you'd have to generate the electricity somehow and you're starting supersonic. So in the end you're burning fuel in an inefficient device to generate power for another inefficient device so by the time you're done you get less use of the fuel you'd be burning to get the power in the first place. It's another, interesting idea that'll never work.

Well, it's a ramjet in the sense that it can behave as a ramjet at high speeds. The electrical components are designed to propel it at low speeds. Presumably, the engine would be started with some kind of auxilary power generator or battery. After the fuel starts burning, energy from the combustion would be used in part to power the engine and in part to produce thrust. I mean, normal jet engines keep on going because of the energy released by combustion, right? You don't have to keep pumping electric power into the shaft to keep the blades turning.
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Unread post03 Mar 2009, 11:44

I’m highly skeptical that the design in your post and diagrams would amount to anything but a fart; I am highly skeptical that electromagnetics could replace a compressor or a turbine on any type of aircraft jet engine. I think there is much more potential to use electromagnetics as a heat source to somehow irradiate the air to make it heat up and expand; however I am skeptical that they would ever be practical either.

LordOfBunnies wrote:It's another, interesting idea that'll never work.

I agree that it’s very interesting to ponder on, I agree that it’ll probably never work practically. However I don’t think I would go as far as to say never. I doubt it’s possible on a practical level, but so far I see no reason to totally rule it out on a theoretical level.
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Unread post03 Mar 2009, 15:35

That would apply to the electrical arc version of the ionization stage, right? What about the electrified grid or the ionizing radiation options? Would those fare better?

Unfortunately, I doubt these would be terribly efficient and the electrified grid would cause quite a large amount of drag. I also doubt either of them would produce enough ions to be useful with using magnets as compressors. I doubt it would be more efficient than using blades as compressors

The problem you run into is that it's still a ramjet. You have to have significant air blowing down it to get it to run in the right direction. Even with the magnetic compressor idea, you have to get it started and keep it running in one direction.

Well, it's a ramjet in the sense that it can behave as a ramjet at high speeds. The electrical components are designed to propel it at low speeds. Presumably, the engine would be started with some kind of auxilary power generator or battery. After the fuel starts burning, energy from the combustion would be used in part to power the engine and in part to produce thrust. I mean, normal jet engines keep on going because of the energy released by combustion, right? You don't have to keep pumping electric power into the shaft to keep the blades turning.


This is incorrect. A jet engine generates power by the use of either and Auxiliary Power Unit (APU) or an Acessories Gearbox. The first, I believe, is basically a turbine that you run while flying from a secondary stream of air. I'll let the F-16 guys point one out. The Acessories Gearbox is a run by a shaft that comes off one of the spools to run a generator. Burning fuel produces no electricity, you have to do stuff to it to convert it to that kind of energy.
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Unread post03 Mar 2009, 18:44

The only large-scale electromagnetic application I've heard of being considered for jet engines is in the area of magnetic/levitating bearings. The trick with those, as I understand, is making them hold tight tolerances while still being able to handle multi-g maneuvering loads and shocks.
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Unread post03 Mar 2009, 19:34

Without the ability to GENERATE vast amounts of electrical power "bladeless-ly" the whole idea is indeed half baked. :D
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Unread post03 Mar 2009, 19:53

I believe the engine will ionize Oxygen atoms only. So it will seperate Nitrogen molecules (and others) from the Oxygen molecules within the air.

Only the Oxygen gas will be compressed -which is 28% of the air- and combustion will be pure Oxygen gas and the fuel.

Of course IF it comes to reality someday???

The TeslaJet :wink:
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Unread post04 Mar 2009, 00:48

Unfortunately, I doubt these would be terribly efficient and the electrified grid would cause quite a large amount of drag.

I guess that I'm not going to get much use out of the engine, but maybe the drag problem could be overcome if you used an electrified engine cone similar to the cones on the SR-71 instead of a grid.

I believe the engine will ionize Oxygen atoms only. So it will seperate Nitrogen molecules (and others) from the Oxygen molecules within the air.

Only the Oxygen gas will be compressed -which is 28% of the air- and combustion will be pure Oxygen gas and the fuel.

Nitrogen can be ionized as well. It depends on the energy applied to it.
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r2d2

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Unread post04 Mar 2009, 04:23

Kryptid wrote:
...........
Nitrogen can be ionized as well. It depends on the energy applied to it.

Why would you want to ionize the Nitrogen gas? You will have pure O2 in the combustion chamber with less -EM- energy spent.
N2 is an inert gas and no one wants to burn N2. Doing so will give you excessive NOx emissions.
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Kryptid

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Unread post04 Mar 2009, 09:05

I figured that ionizing the nitrogen would allow you to move it as well, thus allowing for a higher overall increase in pressurization than if you only moved the oxygen.

Perhaps my idea won't fly as described, but maybe some ingenious young inventor out there could be inspired by it and created something that actually would work.
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Unread post04 Mar 2009, 13:05

Its funny because at one point I though of something very similar. Anyways, another idea I had was to use electromagnetism to start todays jet engines, using it to spin the fans....couple of days later saw a pdf from NASA utilizing the very same idea....should of thought of it sooner.
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Unread post16 May 2010, 23:48

well, i don't think this particular application of electromagnetism in jet engines trumps any current technology. I think the next turn you take in the labyrinth is implying electromagnetic fields outside the jet engine. and powering the field with energy harnessed from the engine. i am a noob. read up on the stealth projects implementation and exploration of utilizing "electro-x" in aircraft. they basically charge the exhaust plume with "millions of volts" thereby naturally charging the leading edge of the plane with a positive field, thus inducing an ion wind effect, and reducing drag at the same time. This is the really cool part, the thermal energy of the exhaust plume is the source of the energy required to produce this huge field of extremely high voltage. So the heat energy of the engines is converted into a magnetic field that theoretically PULLS the aircraft "to some degree," and the heat output is dramatically reduced, the benefits of this should be obvious. lets see, this particular field of electromagnetism is highly theoretical and subject to ignorant mongers. anyway that it for this train of thought. :twisted:
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