Fusion without vacuum

RobertDyck · 2024-10-04 12:24:17

Perhaps GW Johnson could help with this one. It involves fluid dynamics.

A torus aka donut shape. Hot gas deuterium with a little tritium flowing at high subsonic speed. A de Laval nozzle to convert flow to supersonic, and deliberately create shock diamonds. At the apex of the first diamond, ensure has is compressed to fusion ignition pressure and temperature. We're talking 15 million degrees Celsius. Since that's plasma, the shock diamonds could be contained in a magnetic field. But it's not a vacuum bottle. The Lawson Criteria also requires time. The shock diamond exhaust is then allowed to expand, causing thermodynamic gas expansion to cool. The gas would cool to a temperature where the chamber walls can contain it without melting. Only expect to achieve fusion temperature at the apex of the shock diamonds.

Fusion reactions:
²H + ³H → ⁴He + n
²H + ³He → ⁴He + p
²H + ²H → ³H + p (50%)
²H + ²H → ³He + n (50%)

So if apex temperature can get high enough for double deuterium reactions, other fuels are created. 90% of energy is generated by secondary reactions DT and D³He.

Could the torus use electromagnetic dampening to extract energy? And cool before directing gas back to the nozzle? Keep gas flowing fast by RAM jet effects? Extract a tiny bit of gas, use a mass separator to remove ⁴He. Recirculate everything else. Add deuterium as needed.

tahanson43206 · 2024-10-04 13:55:18

This post is reserved for an index to what I hope will be a long series of posts by NewMars members in support of this new topic!

(th)

tahanson43206 · 2024-10-04 15:06:55

For RobertDyck re new topic....

This post is offered to (at least try to) help you set the stage for thoughtful persons to explore your idea, to see if it has an potential.

To begin with, a key element of your proposal appears to be elimination of the standard current practice, which is to evacuate all atoms not needed for an experiment, and simultaneously to admit to the evacuated chamber only those atoms desired for the experiment.

Please clarify the nature of the gas mixture that would exist within your experiment at a net pressure of 1 bar.

Am I correct in assuming your plan would omit atoms which would detract from the success of the experiment?

Please clarify that point, and please add an explanation of how you would remove byproducts of fusion that are not needed to continue the process.

(th)

RobertDyck · 2024-10-04 15:21:00

Yes, the contents of the chamber would be primarily Deuterium with a little Tritium. Initial fusion would be D-T because that has lowest ignition temperature and pressure. Use energy from that to increase temperature and pressure to ignite double Deuterium. Double-D reaction produces 1/10 the energy and is harder to ignite, but it's byproducts are what you need for the other reactions. So a bit of Tritium is used to "prime" the reaction, then it runs on Deuterium fuel. It produces all the Tritium and Helium-3 needed to sustain the reaction. 90% of energy produced by D-T and D-³He reactions.

But don't start with vacuum. Start with 1 atmosphere pressure. As it operates, heat will increase pressure further.

The idea is to operate with a dynamic gas flow that creates a very small but continuous volume of gas compression. Compress the gas at the shock diamond apex to achieve temperature and pressure necessary for fusion. Gas expands from there, and gas expansion causes cooling. So the only thing adjacent to fusing gas is more gas. Where gas touches chamber walls, gas temperature is cool enough that the chamber will not melt.

tahanson43206 · 2024-10-04 15:39:25

This post is intended to (at least try to) encourage further invention while we wait for others to contribute.

It seems to me that this idea might be tested in a CFD program, and while there are fee-paid such programs, there is at least one that does NOT require payment of a fee. I've attempted to set it up, and achieved modest success in persuading the software to at least report that it was running. Much has changed since then, and I expect the system (OpenFOAM) is much better and easier to use.

That said, this ** is ** sophisticated physics and it is reflected in sophisticated mathematics that is then implemented in software.

Fortunately, this forum includes individuals who (I'm pretty sure) could handle a problem at this level.

I would be happy to dust off the IT procedures, if there is someone with the math skills to deal with matrix manipulations.

(th)

RobertDyck · 2024-10-04 22:17:41

Raptor shock diamonds:

Math:
If you double pressure absolute (pressure vs hard vacuum), then you double temperature in degrees Kelvin (degrees above absolute zero). One degree Kelvin equals one degree Celcius, but zero is moved to absolute zero. This means if we start with 300°K (26.85°C) then to achieve 15 million Kelvin requires increasing by 50,000 times. However, if we start with 1,000°K (726.85°C) then achieving the same result only requires increasing by 15,000 times. That means nozzle exit area to mach disk area must be a ratio of 15,000 to 1. Can we achieve this?

tahanson43206 · Yesterday 06:14:57

for Robert Dyck re #6

Thank you for images showing a linear flow of gas.

Your opening for this topic offered the prospect of a torus as the environment in which the experiment is to be performed.

Available forces to keep atoms of gas away from the walls include magnetism, electrostatic force and gravity.

Gravity doesn't seem to be a useful contributor in this situation.

The gas mixture needs to be ionized in order for either of the Maxwell forces to be applied.

No material exists that can serve as a nozzle, but presumably one of the Maxwell forces might be suitable.

All in all, this is certainly an interesting direction to be looking.

Question: Why is the vacuum an issue? Isn't the heart of your proposal the use of shock waves?

Why not look for a way to implement shock waves in the existing stellarators and tokamuks around the world.

As near as I can tell, existing experiments are trying to squeeze ions into a small torus inside the vacuum one, and no one has considered deliberately creating shock waves (that I've read or heard about).

(th)

RobertDyck · Yesterday 17:16:08

Nothing keeps atoms from the walls. It's a torus filled with gas. The nozzle accelerates has to supersonic speed, which is released into gas within the same torus. Gas surrounding the exhaust nozzle is moving subsonic. Supersonic exhaust into subsonic air produces the shock diamonds. Apex of the diamonds is what the diagram calls it a mach disk. Gas expansion cools gas so the subsonic gas is cooler than melting temperature of the chamber walls.

kbd512 · Yesterday 18:15:58

tahanson43206,

Looking at that engine's exhaust flow behavior, I had the same question you did.

Can that sort of flow behavior be replicated using electromagnets to keep the hot plasma away from the walls of the tokamak?

tahanson43206 · Yesterday 18:50:53

For RobertDyck re injection of gas into a torus full of gas at 1 bar ....

OK... I think I get (at least part of your idea)....

In the absence of mathematicians capable of working this problem, we are left for CFD as the only alternative to get beyond hand waving.

I am curious to know if you are injecting tritium into a torus full of deuterium?

What is the state of deuterium? I assume the oxygen has been removed?

Why bother with the torus shape? Why not just stay linear?

(th)

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Fusion without vacuum

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