Carbon nano tube straw for fuel transfer to space

GCNRevenger · 2004-02-29 09:38:51

The smoke stack however only has to compete against gravity for a few hundred feet, not a few hundred miles. I'm not sure you understand the term "vanishingly small:" it means that there is no net flow worth bothering with. Detectable perhaps, but just not enough to do anything useful at all. It might as well be zero flow for any concieveable number or size of these tubes.

Oh and Helium and Hydrogen are pretty stable molecules, hydrogen won't spontainiously react with much without some energy being pumped in, and Helium is the most stable thing there is, virtually nothing outside of a particle accelerator or a Fusion reaction can touch it.

ERRORIST · 2004-02-29 16:29:58

I disagree. If H2 and He make it to space it is not bound to Earth by gravity.Inside the tube it would have nothing to interact with because the purity is almost 100%. Even if it was, the gasses could be forced up the tube, and into space all the way from the ground. This would save billions of dollars trying to shuttle extra fuel to space.

dicktice · 2004-02-29 18:41:36

Why not get someone to do a simulation program, and do some computer runs of your "tube" in action, from sea level at the bottom of Earth's "gravity well," and then report back? Because nobody's going to convince you otherwise.
Now, what about my "tubeless" scheme: Launch frozen water payloads up Mount Kilaminjaro, then use solar heat and thermal junction-generated emf to melt and electrolysize water into H2 and O2 for long-term storage in the same containers, in LEO?

ERRORIST · 2004-03-01 08:10:19

Answer this simple question. Does Hydrogen or Helium escape the gravity of Earth, and make it to space? Yes or No??? The answer will be the same for the tube. BTW sea level is not the bottom of Earths gravity well.

GraemeSkinner · 2004-03-01 08:11:20

I disagree. If H2 and He make it to space it is not bound to Earth by gravity.

Do you mean natural loss of Hydrogen and Helium from the exosphere?

GCNRevenger · 2004-03-01 08:26:20

It is not bound by gravity IF you can actually get it into orbit, but you can't get signifigant amounts up the tube against gravity - it is a simple kenetic distribution problem, that you can't make the gas molecules move fast enough. So, you just can't move much gas this way. No computer simulations are needed: a fly can't pull a battleship, nor an ant move a moutain... If its only a few grams or milligrams a day or somthing, it simply isn't worth the expense. Plus, even a modest application of pressure would simply not be effective; Venus has about the same gravity as Earth and its pressure is over a hundred times what it is here.

ERRORIST · 2004-03-01 08:28:50

Troposhere, stratosphere, mesosphere. Ionosphere and thermosphere = exosphere.
H2 or He escapes them all. Gravity can not contain H2 or He to earth. Perhaps, the magnetosphere can though but not all of it???

GraemeSkinner · 2004-03-01 08:37:37

Troposhere, stratosphere, mesosphere. Ionosphere and thermosphere = exosphere.
H2 or He escapes them all. Gravity can not contain H2 or He to earth. Perhaps, the magnetosphere can though but not all of it???

As already mentioned earlier in this thread, the natural loss of H2 and He is caused by the molecules gaining energy from an external source, and therefore reaching escape velocity. The H2/He in a nanotube would not be exposed to this source of energy (ok it would gain a bit of energy from solar heating) but otherwise the molecules would just sit there. Loss of H2/He from the atmosphere is minimal, and so is not a good advert for the nanotube straw. Unless someone sets up a computer simulation (as someone mentioned earlier), or builds a working tube that proves the theory I just don't think the physics fit the theory.

ERRORIST · 2004-03-01 08:39:20

One must not forget that the energy will be conserved within the tube. So the differential of pressure between space at one open end and sea level the other open end is what creates the flow. Pressure difference = flow no matter how you look at it, and no matter how long it is.

GraemeSkinner · 2004-03-01 08:48:50

One must not forget that the energy will be conserved within the tube. So the differential of pressure between space at one open end and sea level the other open end is what creates the flow. Pressure difference = flow no matter how you look at it, and no matter how long it is.

If this was a spaceship in orbit with a tube running from the inside out to space the pressure difference would create a flow, however you are still not counting gravity into your equation, until you can explain how you get the H2/He to reach escape velocity I'm still keeping my hat on my head :;):

ERRORIST · 2004-03-01 08:58:05

Look at a hydrogen or a helium filled balloon as it goes up, and gravity does not hold it to Earth. The hydrogen or helium would continue to go up to space, if it was not contained in the rubber. Who would want to run a computer model just to see what would happen?

GraemeSkinner · 2004-03-01 09:23:19

If the Hydrogen or Helium was not contained in the balloon it would just disperse into the atmosphere.
I certainly would want to run a computer simulation on such a theory, you can not seriously tell me that you'd just spend millions on construction of a nanotube just because you suspect your theory is correct - regardless of your view on the nanotube straw (will it or won't it work) a good computer simulation would give you a rate of flow to establish if it was worth building.

ERRORIST · 2004-03-01 09:49:15

Man if I had money to waste like Bill Gates I would build all kinds of stuff. Even if it didn't work. It would stimulate the mind to think of something new to build.
The gas may even accelerate inside the tube since the energy and kinetics are conserved inside the tube. As the radius extends further and futher from the axis the gas may even accelerate along the tube. It reminds me of a pump impeller slinging the water outward from it vanes due to its rotational velocity. Could the Earth actually be a large pump?????

GraemeSkinner · 2004-03-01 11:03:25

Forgot to mention in my response regarding the helium balloon, that they have a height range of around 20 miles, this is when the weight of the helium molecules are no longer lighter than the surrounding air. So this does not support the nano tube theory.

ERRORIST · 2004-03-01 15:10:23

At the height of 20 miles the Helium is still enclosed inside the rubber balloon, what happens? It becomes neutrally bouyant within the atmosphere because it still has the weight of the rubber balloon surrounding it,and it can't continue up further. Now pop the balloon.The Helium continues on up,and into space.

GCNRevenger · 2004-03-01 18:14:40

Troposhere, stratosphere, mesosphere. Ionosphere and thermosphere = exosphere.
H2 or He escapes them all. Gravity can not contain H2 or He to earth. Perhaps, the magnetosphere can though but not all of it???

Actually, yes it can... you want numbers ey? Let me direct you to any decent college chemistry textbook (Hill and Pertucci's is the one I use) and look up the Kenetic Theory of Gases. Here you will see that the average velocity of a hydrogen molecule at modest temperature is around 1,500m/s. Somewhat substantial portions reach speeds of up to 3,000m/s, almost zilch above this, it goes to zero. There are essentially no molecules beyond this speed distribution.

The escape velocity of the Earth, barring outside influences which the straw would shield anyway, is 11,000m/s... ten times the average at room temperature, and nearly four times beyond any useful quantity. You can't raise the pressure substantially without introducing a host of problems, and you can't raise the temperature all the way to orbit... Hydrogen and Helium do leave the Earth, just not very fast at all. The reason there isn't much around is not because it readily escapes, but because most of the Hydrogen has reacted with Oxygen to make water, and there is little Helium to begin with. Nitrogen, Oxygen, etc also escape, but much slower than even the light gasses.

There you have it... 11,000 >> 3,000m/s.

ERRORIST · 2004-03-01 18:57:47

There is nothing for H2 to react with inside the tube. Therefore, it will rise into space. Pressure difference = Flow.Energy is conserved inside the tube. Physics says so not me.
Nitrogen, Oxygen, etc also escape, but much slower than even the light gasses. These molecules escape at a lower velocity because they are more massive, and gravity wants to hold them to the Earth longer.

GCNRevenger · 2004-03-01 20:27:50

Ah but that IS for pure hydrogen, and not a mixture gasses, under ideal circumstances... again, physics does not preclude some hydrogen molecules making it up the tube, and infact makes provision for it; however the physics of gravity apply to all forms of matter, gasses included, which state that virtually all the gas will never make it.

Furthermore, space is a cold place generally speaking, which will inevitibly lower the gasses' temperature even further, which will drive down its velocity even more... so what was a non-exsistant hardly detectable flow even is now a statistical improbability. I estimate you would have to raise the temperature of the gas to a temperature high enough to decompos the carbon nanotube straw before you would even see any quantity of hydrogen, much less enough to be useful.

ERRORIST · 2004-03-01 21:04:48

H2 would make it out of the atmosphere, and into space in greater volumes if it had no oxygen to react with. Right?

GCNRevenger · 2004-03-01 21:30:10

No, the hydrogen gas would not make it into space efficently even if it were pure - even isotopicly pure - of all other gasses oxygen included.

ERRORIST · 2004-03-01 23:53:59

I disagree.

GraemeSkinner · 2004-03-02 00:34:35

At the height of 20 miles the Helium is still enclosed inside the rubber balloon, what happens? It becomes neutrally bouyant within the atmosphere because it still has the weight of the rubber balloon surrounding it,and it can't continue up further. Now pop the balloon.The Helium continues on up,and into space.

No, it would not raise much higher if you popped the balloon but would again be dispersed into the surrounding atmosphere.
I don't think anything I say will convince you Errorist that the straw would only provide a trickle of molecules into space so I think I'll agree to disagree on the matter, or we could be here for a long time :;):

ERRORIST · 2004-03-02 00:46:32

Yea, we would be here forever like two rams butting heads.

Hey, here is another thought. What if you shot a particle beam of hydrogen up the tube with out it hitting the sides?

GCNRevenger · 2004-03-02 08:50:35

Oookay, you disagree with what what notion again?

A particle beam can't move substantial masses either, they are even worse than ion engines which would take years to move even a few hundred kilos. Also, aiming one down a narrow tube 24,000mi long without hitting the sides is not going to happen.

ERRORIST · 2004-03-02 09:03:54

It was just a thought. Although, particle beams can now shoot down incoming ballistic missles from a 747. It exhausts the H2 particles at very high energies thus burning a hole in the target, all the hydrogen is used up after a number of bursts.

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#26 2004-02-29 09:38:51

Re: Carbon nano tube straw for fuel transfer to space

#27 2004-02-29 16:29:58

Re: Carbon nano tube straw for fuel transfer to space

#28 2004-02-29 18:41:36

Re: Carbon nano tube straw for fuel transfer to space

#29 2004-03-01 08:10:19

Re: Carbon nano tube straw for fuel transfer to space

#30 2004-03-01 08:11:20

Re: Carbon nano tube straw for fuel transfer to space

#31 2004-03-01 08:26:20

Re: Carbon nano tube straw for fuel transfer to space

#32 2004-03-01 08:28:50

Re: Carbon nano tube straw for fuel transfer to space

#33 2004-03-01 08:37:37

Re: Carbon nano tube straw for fuel transfer to space

#34 2004-03-01 08:39:20

Re: Carbon nano tube straw for fuel transfer to space

#35 2004-03-01 08:48:50

Re: Carbon nano tube straw for fuel transfer to space

#36 2004-03-01 08:58:05

Re: Carbon nano tube straw for fuel transfer to space

#37 2004-03-01 09:23:19

Re: Carbon nano tube straw for fuel transfer to space

#38 2004-03-01 09:49:15

Re: Carbon nano tube straw for fuel transfer to space

#39 2004-03-01 11:03:25

Re: Carbon nano tube straw for fuel transfer to space

#40 2004-03-01 15:10:23

Re: Carbon nano tube straw for fuel transfer to space

#41 2004-03-01 18:14:40

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#42 2004-03-01 18:57:47

Re: Carbon nano tube straw for fuel transfer to space

#43 2004-03-01 20:27:50

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#44 2004-03-01 21:04:48

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#45 2004-03-01 21:30:10

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#46 2004-03-01 23:53:59

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#47 2004-03-02 00:34:35

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#48 2004-03-02 00:46:32

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#49 2004-03-02 08:50:35

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#50 2004-03-02 09:03:54

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