...Fragment Nuclear Reactor
Next Big Future did it again and has a very interesting article for all us space buffs here:
http://nextbigfuture.com/2010/03/dusty- ... gment.html
Now to me this sounds- at least in theory- quite promising... to promising for my personal liking. 180kg of nuclear fuel sounds waaay to little.
Still, if that works, it would be pretty cool, no question about it.
Dusty Plasma Based Fission...
As long as you can wait a hundred years or so for engine repairs....
And never start it up any where near a inhabited environment...
And shields up....
And do your initial testing on the moon....
Spewing protons is going to be an easier sell than spewing fission fragments.
And never start it up any where near a inhabited environment...
And shields up....
And do your initial testing on the moon....
Spewing protons is going to be an easier sell than spewing fission fragments.
Engineering is the art of making what you want from what you can get at a profit.
From the article:
"The fission fragments or decay products accelerated during the disintegration process to velocities of 3-5% of the speed of light are trapped and collected in a simple combination of electric and magnetic fields resulting in a highly efficient (90%), non-Carnot, DC power supply. "
I'm not going to argue with you MSimon, but I entreat to better your education about thermodynamics and realize not every prime mover is Carnot limited.
Carnot applies to heat engines with a working fluid doing mechanical work via pressure moving through a distance a la Boyle's Law. The direct conversion mechanism of the Polywell and this dusty gaseous reactor are not subject to Carnot.
"The fission fragments or decay products accelerated during the disintegration process to velocities of 3-5% of the speed of light are trapped and collected in a simple combination of electric and magnetic fields resulting in a highly efficient (90%), non-Carnot, DC power supply. "
I'm not going to argue with you MSimon, but I entreat to better your education about thermodynamics and realize not every prime mover is Carnot limited.
Carnot applies to heat engines with a working fluid doing mechanical work via pressure moving through a distance a la Boyle's Law. The direct conversion mechanism of the Polywell and this dusty gaseous reactor are not subject to Carnot.
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I do not believe that I made any objection to this device on Carnot grounds.I'm not going to argue with you MSimon, but I entreat to better your education about thermodynamics and realize not every prime mover is Carnot limited.
Secondly Giorgio and I agree about the device he did present on Carnot grounds.
He was considering one aspect of the device and I another. When the miscommunication was resolved we found we were in agreement.
So it may be that my understanding of Carnot is not deficient as you suggest.
Engineering is the art of making what you want from what you can get at a profit.
Not true the way you think it is. Carnot requires the movement of heat through a medium which changes temperature as an irreducible aspect of the production of energy. The Polywell may have it's high temperature as an inherent aspect of it's mechanism of energy creation, but it is not required for the ions to be hot for the direct conversion to work. Ions that stay the same temperature work just as well.
For example the abstract of this paper:
http://journals.pepublishing.com/conten ... 833473501/
It is not required for Carnot's efficiency to be a limit on a process for the 2nd law to be shown to be true.
For example the abstract of this paper:
http://journals.pepublishing.com/conten ... 833473501/
It is not required for Carnot's efficiency to be a limit on a process for the 2nd law to be shown to be true.
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para fides paternae patria
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Ions at 3 MeV are rather hot. Roughly 11,605 deg K/ ev. And if they aren't cooled by the energy collector you will get no energy out of them.Ions that stay the same temperature work just as well.
And I think of Carnot these days in a statistical thermodynamics way.
Now can you cool those 3 MeV ions with out affecting the other ions in the mix - in theory yes. Since the ions are not statistically coupled due to collisions Carnot need not apply.
My understanding may be more sophisticated than you give me credit for. I have studied the question in some depth. Probably 3rd or 4th year undergrad level. Maybe higher. I can't say for sure. I don't know much about what is taught in a university.
Engineering is the art of making what you want from what you can get at a profit.
MSimon, if your numbers hold that would be 3.48*10^10 deg K, I think.
Polywells aren't that hot. The ions do move along, yet they are not the heatsource you are fumbling for. This is not a heat engine, Boyle's law and the associated enthalphy is not at issue, except at meaningless margins.
The energies involved can be expressed as equivalent temperature, but Carnot engines and like limited cycles do not run on equivalent temperature, they run on actual thermometer temperature.
Why do you think direct conversion required the ions begin hot and end cold? It only requires the movement, not temperature.
Polywells aren't that hot. The ions do move along, yet they are not the heatsource you are fumbling for. This is not a heat engine, Boyle's law and the associated enthalphy is not at issue, except at meaningless margins.
The energies involved can be expressed as equivalent temperature, but Carnot engines and like limited cycles do not run on equivalent temperature, they run on actual thermometer temperature.
Why do you think direct conversion required the ions begin hot and end cold? It only requires the movement, not temperature.
molon labe
montani semper liberi
para fides paternae patria
montani semper liberi
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Dude,TDPerk wrote:MSimon, if your numbers hold that would be 3.48*10^10 deg K, I think.
Polywells aren't that hot. The ions do move along, yet they are not the heatsource you are fumbling for. This is not a heat engine, Boyle's law and the associated enthalphy is not at issue, except at meaningless margins.
The energies involved can be expressed as equivalent temperature, but Carnot engines and like limited cycles do not run on equivalent temperature, they run on actual thermometer temperature.
Why do you think direct conversion required the ions begin hot and end cold? It only requires the movement, not temperature.
I have discussed this with Tom Ligon (who ought to know) and I'm in fact correct. If you want he talks about it at NASA Spaceflight. Long discussion there. It was discussed in the context of toks.
What you mean is that the output is not Maxwellian in the sense of having a range of velocities in the X,Y,Z planes.
But it is at that temperature. And if you care, call in Art Carlson and ask him.
Temperature is about average energy. And if you have a group of particles all moving towards the wall at identical velocities they do have a temperature in the lab frame of reference and it is described by the Boltzman constant given.
Now such a way of describing what is going on may or may not be useful but Boltzman says temp = 11,605 deg K/eV. There is nothing you can do about ir.
Engineering is the art of making what you want from what you can get at a profit.
And if you care go back to the temperature driven fuel cell thread and read the conclusion.
Short version: Outside the fuel cell the process is subject to Carnot. i.e. the separation of hot ions from cooler ones on the hot side.
Once the ions are in the fuel cell it is a chemical process not subject to Carnot.
Girgio (sp?) and I agree. Care to join us?
Short version: Outside the fuel cell the process is subject to Carnot. i.e. the separation of hot ions from cooler ones on the hot side.
Once the ions are in the fuel cell it is a chemical process not subject to Carnot.
Girgio (sp?) and I agree. Care to join us?
Engineering is the art of making what you want from what you can get at a profit.