Centrifugal pulsed fusor, concept idea

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Mike willcox
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Centrifugal pulsed fusor, concept idea

Post by Mike willcox »

I've been mulling over the problems with energy losses for some time, and i've devised a concept that i'd like to bounce off the community. please be as brutal as possible in the comments.

Construction is a disc shaped chamber, or possibly a squashed sphere. its rotating extremely fast, perhaps a little like a gas centrifuge used for UF6 separation. The rotation means that all the deuterium in the vessel is pressed against the walls, leaving a vacuum in the middle.

the cathode in the middle perhaps takes the form of 2 flat plates, one top, one bottom such that there is a space between them in the middle of the chamber.
metal ring anode goes round the inside circumference


the device is operated by applying very short pulses of high voltage to the central cathode (same voltage on both) relative to the anode. thus the ions that are at the device walls are now accelerated to the centre.
but its only a very short high frequency voltage pulse, it has dropped back to 0 before the ions reach them, and because the ions all start from the inside wall rather than from random positions in the device, their time of flight to the middle is relatively constant and predictable, this allows for optimisation of the frequency needed.

so because the voltage is off by the time the ions reach the middle, there is no wasted current with ions hitting the electrodes and transferring charge, also because the cathode is two plates facing each other with a space in the middle, the ions are attracted towards the space in the middle, not the metal itself, so you also get fewer wasted collisions with the metal, whereas in a standard fusor the grid is very much in the path of the ions.


ions that do not fuse, will of course scatter as normal into random directions, their impacts with the walls will of course waste their energy as heat, so i still don't think this device would be anywhere near energy break even.
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Richard Hull
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Re: Centrifugal pulsed fusor, concept idea

Post by Richard Hull »

At fusion pressures there is little of no molecular drag (viscous flow). what little there is would require tens of thousands of RPM. Then there is the issue of continuous differential pumping at that speed. (vacuum port vacuum tight and the gas port also not leaky). Just my first thoughts.

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
John Futter
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Re: Centrifugal pulsed fusor, concept idea

Post by John Futter »

Mike
How about following rules for this
site!!
look up Chris Bradleys efforts on this site
ie Crimson donuts
please introduce yourself

etc etc
Mike willcox
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Re: Centrifugal pulsed fusor, concept idea

Post by Mike willcox »

ok my apologies, have just posted an introduction
John Futter
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Re: Centrifugal pulsed fusor, concept idea

Post by John Futter »

Excellent
and welcome
Mike willcox
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Re: Centrifugal pulsed fusor, concept idea

Post by Mike willcox »

Ok so taking Richards reply concerned about the lack of molecular drag at such low pressures. Some thoughts on this.

My idea of combining a fusor with a gas centrifuge, is merely to create a pressure gradient, with most of the gas at the walls, and minimum amount in the centre.
i know a little about the gas centrifuges used to enrich UF6, these actually do operate at very low pressures, - approx 0.001 atmospheres (or 100 Pa) (REF https://physicstoday.scitation.org/doi/ ... /1.2982121)

i understand the fusors operate about 0.1 - 2.5 Pa (found a post on here, and converted from Torr to Pa) so its a fair bit lower pressure, but the point is the gas centrifuges work best on very low pressure gas. as long as you are able to impart rotational speed to the atoms on the spinning wall, there will be a potential energy gradient they have to overcome to reach the middle. if the atoms need some encouragement to spin along with the moving wall, you could always put some ridges on it.

I was not necessarily thinking of the need for high vacuum tight ports for continuous pumping, if you change the vessel with a controlled initial fill of low pressure D then, seal it up, no need for moving seals, although the UF6 gas centrifuges manage this quite well with scoops to collect the gas fractions (attached a document)

the document I attached has a formula for calculating the pressure gradient across a gas centrifuge. its actually not exactly what is needed for this, as you'd need a separate quite complicated calculation to work out how much gas to add at the start to get the desired pressures


but as an example calculation. if i want the D pressure in the centre to be very low, say 0.001 Pa (7.5E-6 Torr) if I had a rotor diameter of radius 0.2m, spinning at 13000 RPM, and a temperature of 250 celcius (523K) then i get a wall pressure of 25000 Pa (about 0.25 bar)



Thats assuming the molecular mass being 2 of course for D, temperature of 250 chosen in case by some miracle it were energy positive, you'd want to be able to extract heat from it, but higher temperatures drastically reduce the pressure gradient you get.
i'd need to look at the strengths of materials to look at the maximum RPM rate that would actually be feasible for a given rotor diameter, that one was just an initial stab. the UF6 gas centrifuges operate right at the limits of materials capabilities, I think this wouldn't need to be quite as extreme.


any input on this gratefully received,
Attachments
Factsheet-Urenco.pdf
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Richard Hull
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Re: Centrifugal pulsed fusor, concept idea

Post by Richard Hull »

Sound like a cracker-jack idea. Now money and hands-on effort where the mouth is..........You build it! I promise you, none of us will!
You might say it is just an idea, a theory of how I think we can do this. Fine.
I have some of my very finest thoughts and ideas and theories and the local Starbucks will, If I tell them all my ideas and give them $6.75 will present me with a mocha latte supreme with extra whipped stuff.
If you really have a good deal of faith in your idea, can you turn it into something real? Until then it is, and always will remain, a cracker-jack idea floating about the internet aether.
If you build this thing, we will listen in rapt awe, even if it fails. You know why, we want to learn what went wrong and why it did not work. Those are as important as a win.

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
Mike willcox
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Joined: Tue Sep 10, 2019 2:36 am
Real name: Mike Willcox

Re: Centrifugal pulsed fusor, concept idea

Post by Mike willcox »

Haha, Thanks Richard, I quite agree that ideas are worthless unless acted upon.

I certainly aspire to have a go building this thing some time, although the engineering challenges involved do seem tall. it seemed worthwhile bouncing the idea off other people before embarking on such a project though.
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