A while back I had a conversation concerning the Carbon Fiber tanks and
their insulation on the DC-X Program flight vehicle with one of the senior
engineers.
I don't recall too much about the LOX tank but the LH2 tank conversation
was interesting.
They used internal insulation (type ?) with the carbon fiber tank keeping
the overall weight under control.
This was of course a reusable, light pressure vessel tank, that according
to the information provided did not show any signs of microfracture of the
CF Epoxy matrix.
The Epoxy was a conventional grade used on aerospace structures i.e no
special PTFE additives etc.
I was not able to find out though what type of non permeable barrier lay on
top of the insulation or the type of and density of the insulation used.
If anyone can comment on that, it would be appreciated. Thank you!
Cheers
Brian Feeney
On Sun, Jun 23, 2019, 6:57 PM Troy Prideaux, <troy@xxxxxxxxxxxxxxxxxxxxx>
wrote:
Probably removes the flammability issue, but likely makes the other issues
Am 22.06.2019 um 01:01 schrieb Paul Mueller:
At least with polyurethane (I think that's right) spray-on foam
insulation, the cold-side cells will cryopump/cryoevacuate down
initially. But over time (days to weeks), atmospheric gas will diffuse
through the cell walls, reducing the effectiveness of the insulation.
In the (Earth's) atmosphere, this can potentially cause an oxygen
enriched atmosphere inside the flammable foam, kind of risky for a
hydrogen system.
What happens if you put the insulation on the inside? :-)
Uwe
*worse* ie. thermal conductivity, insulation permeation, higher pressure
differentials on the insulation etc.
Troy
