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High strength fibers for hydrogen storage on the VentureStar.



 
 
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  #1  
Old July 29th 08, 05:59 PM posted to sci.astro,sci.space.policy,sci.physics,sci.energy
Robert Clark
external usenet poster
 
Posts: 1,150
Default High strength fibers for hydrogen storage on the VentureStar.

Nice articles here on the problems that led to the cancellation of the
VentureStar/X-33, a single-stage to orbit vehicle:

Lockheed Martin X-33.
http://en.wikipedia.org/wiki/Lockheed_Martin_X-33

X-33/VentureStar - What really happened.
http://www.nasaspaceflight.com/content/?id=4180

Interestingly the main problem was making the liquid hydrogen tanks
light enough, certainly not a high tech problem. I wonder if
lightweight storage could be achieved by storing the hydrogen in very
many micron-scale hollow fibers. See the table of tensile strengths
listed he

Tensile strength.
http://en.wikipedia.org/wiki/Tensile_strength

The solutions investigated for the hydrogen tanks for VentureStar
included using high strength aluminum alloys or composite fiber tanks.
The composite tanks were lighter but had a problem of debonding under
high pressure. Note in the table of tensile strengths carbon fiber has
a better strength to weight ratio than the aluminum alloy listed by a
factor of 19 to 1. And the high strength glass fibers known as S-glass
is better than the aluminum alloy by 10 to 1. There is also a special
steel fiber known as scifer steel not listed in the table that has a
tensile strength of 5500 MPa at a density of 7.8 g/cc. That is better
than aluminum alloy by a factor of 4 to 1. It might even be for the
carbon fibers and the S-glass fibers their strength to weight ratios
are so high you wouldn't need to store the hydrogen in liquid form.
You could store it as high density gas. That would eliminate the
weight of the cryogenic systems for the hydrogen.
However, a key question here is whether this strength will be
maintained in the radial direction. All the strengths listed for the
fibers are for pulling along their lengths, i.e, their longitudinal
tensile strength. But to use the fibers as thin hollow pressure tubes
will require their strength to hold in the radial direction. After
investigating this question before for hydrogen storage, I know that S-
glass and scifer steel fibers do retain that strength in the radial
directions. I'm not sure if this is true for the carbon fiber. (BTW,
the high strength polymer fibers listed in the table such as Kevlar,
Dyneema, or Spectra are unsuitable because their strength only holds
in the longitudinal direction, not radially.)
Another key problem for using high strength fibers as hollow tubes is
that they are only about 10 microns wide. So millions to billions of
them would be needed to form sizable storage tanks. You would need a
method of opening and closing these microscopically thin tubes at the
same time for a throttleable engine. Perhaps one solution would be to
have only a small portion of them being used at any one time and
letting those completely empty out, then open another portion, and so
on until all the fuel is used up. This would be an easier solution
than having so many precisely controlled valves at the micro-scale
that operated all in unison.


Bob Clark
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  #2  
Old July 29th 08, 06:12 PM posted to sci.astro,sci.space.policy,sci.physics,sci.energy
BradGuth
external usenet poster
 
Posts: 21,544
Default High strength fibers for hydrogen storage on the VentureStar.

On Jul 29, 9:59 am, Robert Clark wrote:
Nice articles here on the problems that led to the cancellation of the
VentureStar/X-33, a single-stage to orbit vehicle:

Lockheed Martin X-33.http://en.wikipedia.org/wiki/Lockheed_Martin_X-33

X-33/VentureStar - What really happened.http://www.nasaspaceflight.com/content/?id=4180

Interestingly the main problem was making the liquid hydrogen tanks
light enough, certainly not a high tech problem. I wonder if
lightweight storage could be achieved by storing the hydrogen in very
many micron-scale hollow fibers. See the table of tensile strengths
listed he

Tensile strength.http://en.wikipedia.org/wiki/Tensile_strength

The solutions investigated for the hydrogen tanks for VentureStar
included using high strength aluminum alloys or composite fiber tanks.
The composite tanks were lighter but had a problem of debonding under
high pressure. Note in the table of tensile strengths carbon fiber has
a better strength to weight ratio than the aluminum alloy listed by a
factor of 19 to 1. And the high strength glass fibers known as S-glass
is better than the aluminum alloy by 10 to 1. There is also a special
steel fiber known as scifer steel not listed in the table that has a
tensile strength of 5500 MPa at a density of 7.8 g/cc. That is better
than aluminum alloy by a factor of 4 to 1. It might even be for the
carbon fibers and the S-glass fibers their strength to weight ratios
are so high you wouldn't need to store the hydrogen in liquid form.
You could store it as high density gas. That would eliminate the
weight of the cryogenic systems for the hydrogen.
However, a key question here is whether this strength will be
maintained in the radial direction. All the strengths listed for the
fibers are for pulling along their lengths, i.e, their longitudinal
tensile strength. But to use the fibers as thin hollow pressure tubes
will require their strength to hold in the radial direction. After
investigating this question before for hydrogen storage, I know that S-
glass and scifer steel fibers do retain that strength in the radial
directions. I'm not sure if this is true for the carbon fiber. (BTW,
the high strength polymer fibers listed in the table such as Kevlar,
Dyneema, or Spectra are unsuitable because their strength only holds
in the longitudinal direction, not radially.)
Another key problem for using high strength fibers as hollow tubes is
that they are only about 10 microns wide. So millions to billions of
them would be needed to form sizable storage tanks. You would need a
method of opening and closing these microscopically thin tubes at the
same time for a throttleable engine. Perhaps one solution would be to
have only a small portion of them being used at any one time and
letting those completely empty out, then open another portion, and so
on until all the fuel is used up. This would be an easier solution
than having so many precisely controlled valves at the micro-scale
that operated all in unison.

Bob Clark


How about instead of LH2, using h2o2 at 98% purity. 100% h2o2 is
essentially a crystal like solid.

How about using a basalt fiber and micro-balloon composite as the
primary structural shell or containment vessel on behalf of whatever
fluid storage tank? (it can even be plasma metallic coated on the
inside)

h2o2 along with a little synfuel is actually offering a better
volumetric density worth of stored energy in a fluid format that's not
the least bit cryogenic or even all that vapor prone.

- Brad Guth Brad_Guth Brad.Guth BradGuth
  #3  
Old August 1st 08, 08:46 PM posted to sci.astro,sci.space.policy,sci.physics,sci.energy
D. Orbitt
external usenet poster
 
Posts: 33
Default High strength fibers for hydrogen storage on the VentureStar.

Did they look at using aerogel to fill in the honeycombs instead of
the heavier foam insulation?

I like to think that the air force and DOD/CIA took all the parts and
made something anyway, something that's flying right now, probably
unmanned.
  #4  
Old August 2nd 08, 03:39 AM posted to sci.astro,sci.space.policy,sci.physics,sci.energy
BradGuth
external usenet poster
 
Posts: 21,544
Default High strength fibers for hydrogen storage on the VentureStar.

On Aug 1, 12:46 pm, "D. Orbitt" wrote:
Did they look at using aerogel to fill in the honeycombs instead of
the heavier foam insulation?

I like to think that the air force and DOD/CIA took all the parts and
made something anyway, something that's flying right now, probably
unmanned.


DARPA does whatever they want and whenever they want, without asking
or telling. (it's a Zionist/Nazi kind of New World Order thing, that
we're not supposed to understand)

* Brad Guth Brad_Guth Brad.Guth BradGuth
  #5  
Old August 4th 08, 08:23 PM posted to sci.astro,sci.space.policy,sci.physics,sci.energy
Jeff Findley
external usenet poster
 
Posts: 5,012
Default High strength fibers for hydrogen storage on the VentureStar.


"D. Orbitt" wrote in message
...
Did they look at using aerogel to fill in the honeycombs instead of
the heavier foam insulation?

I like to think that the air force and DOD/CIA took all the parts and
made something anyway, something that's flying right now, probably
unmanned.


That would be a neat trick, considering the tanks failed during testing.
And we're not talking a little failure here. We're talking about big time
structural failure.

Jeff
--
A clever person solves a problem.
A wise person avoids it. -- Einstein


  #6  
Old August 4th 08, 09:28 PM posted to sci.astro,sci.space.policy,sci.physics,sci.energy
[email protected]
external usenet poster
 
Posts: 558
Default High strength fibers for hydrogen storage on the VentureStar.

On Aug 1, 3:46 pm, "D. Orbitt" wrote:


I like to think that the air force and DOD/CIA took all the parts and
made something anyway, something that's flying right now, probably
unmanned.


Not really possible. Can't hide operations of a vehicle that size

  #7  
Old August 10th 08, 12:32 AM posted to sci.astro,sci.space.policy,sci.physics,sci.energy
Robert Clark
external usenet poster
 
Posts: 1,150
Default High strength fibers for hydrogen storage on the VentureStar.

On Jul 29, 12:59 pm, Robert Clark wrote:
Nice articles here on the problems that led to the cancellation of the
VentureStar/X-33, a single-stage to orbit vehicle:

Lockheed Martin X-33.http://en.wikipedia.org/wiki/Lockheed_Martin_X-33

X-33/VentureStar - What really happened.http://www.nasaspaceflight.com/content/?id=4180

Interestingly the main problem was making the liquid hydrogen tanks
light enough, certainly not a high tech problem. I wonder if
lightweight storage could be achieved by storing the hydrogen in very
many micron-scale hollow fibers. See the table of tensile strengths
listed he

Tensile strength.http://en.wikipedia.org/wiki/Tensile_strength

The solutions investigated for the hydrogen tanks for VentureStar
included using high strength aluminum alloys or composite fiber tanks.
The composite tanks were lighter but had a problem of debonding under
high pressure. Note in the table of tensile strengths carbon fiber has
a better strength to weight ratio than the aluminum alloy listed by a
factor of 19 to 1. And the high strength glass fibers known as S-glass
is better than the aluminum alloy by 10 to 1. There is also a special
steel fiber known as scifer steel not listed in the table that has a
tensile strength of 5500 MPa at a density of 7.8 g/cc. That is better
than aluminum alloy by a factor of 4 to 1. It might even be for the
carbon fibers and the S-glass fibers their strength to weight ratios
are so high you wouldn't need to store the hydrogen in liquid form.
You could store it as high density gas. That would eliminate the
weight of the cryogenic systems for the hydrogen.
However, a key question here is whether this strength will be
maintained in the radial direction. All the strengths listed for the
fibers are for pulling along their lengths, i.e, their longitudinal
tensile strength. But to use the fibers as thin hollow pressure tubes
will require their strength to hold in the radial direction. After
investigating this question before for hydrogen storage, I know that S-
glass and scifer steel fibers do retain that strength in the radial
directions. I'm not sure if this is true for the carbon fiber. (BTW,
the high strength polymer fibers listed in the table such as Kevlar,
Dyneema, or Spectra are unsuitable because their strength only holds
in the longitudinal direction, not radially.)
Another key problem for using high strength fibers as hollow tubes is
that they are only about 10 microns wide. So millions to billions of
them would be needed to form sizable storage tanks. You would need a
method of opening and closing these microscopically thin tubes at the
same time for a throttleable engine. Perhaps one solution would be to
have only a small portion of them being used at any one time and
letting those completely empty out, then open another portion, and so
on until all the fuel is used up. This would be an easier solution
than having so many precisely controlled valves at the micro-scale
that operated all in unison.

Bob Clark


Another possible solution to having so many tubes release the
hydrogen in unison might be to have them bound together with one end
closed and the other end left open but with a cap over the open end of
all of them made of a high strength material to which would be
connected the controlling valve. Since the end cap would have a much
smaller size than the full tank you could afford to have it be thicker
so as to withstand the pressure of the fuel without it taking up too
much weight. You would need though to have a strong bond between the
material of the end cap and the material composing the separate
microtubes.

Bob Clark
  #8  
Old August 10th 08, 05:15 PM posted to sci.astro,sci.space.policy,sci.physics,sci.energy
Bret Cahill
external usenet poster
 
Posts: 29
Default High strength fibers for hydrogen storage on the VentureStar.

Hoop stresses of a tube under pressure increase with the diameter but
volume increases with the square of diameter. High volume/weight
pressurised gas storage would, therefore, favor a bigger cylinder.


Bret Cahill




  #9  
Old August 11th 08, 02:10 AM posted to sci.astro,sci.space.policy,sci.physics,sci.energy
David M. Palmer
external usenet poster
 
Posts: 156
Default High strength fibers for hydrogen storage on the VentureStar.

In article
,
Bret Cahill wrote:

Hoop stresses of a tube under pressure increase with the diameter but
volume increases with the square of diameter. High volume/weight
pressurised gas storage would, therefore, favor a bigger cylinder.


That's a wash. Container weight scales with area times thickness, and
thickness scales with hoop stress, so the weight scales as
(diameter*length) * diameter, just as volume does.

(Neglecting minimum gauge and other non-theoretical effects.)

--
David M. Palmer (formerly @clark.net, @ematic.com)
  #10  
Old August 11th 08, 04:39 AM posted to sci.astro,sci.space.policy,sci.physics,sci.energy
[email protected]
external usenet poster
 
Posts: 9
Default High strength fibers for hydrogen storage on the VentureStar.

Hoop stresses of a tube under pressure increase with the diameter but
volume increases with the square of diameter. �High volume/weight
pressurised gas storage would, therefore, favor a bigger cylinder.


. . .

Container weight scales with area times thickness, and
thickness scales with hoop stress,


But the area and volume increase with the diameter _squared_.


Bret Cahill


 




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