When designing LOx systems I use fluid velocity as a criteria not metal
type. I keep LOx velocities 50% lower than the Kerosene counterpart.
The reason for this is if there are any partilates in the LOx the
probability of an impact leading to an ignition goes up with velocity.
So as a very general rule, 15 Ft/Sec for LOx and 25Ft/sec for kerosene and
double to triple that through ball valves.
The Saturn 5 tanks were 2219 aluminum alloy and Shuttle ET lithium/aluminum
alloy in the latter version and 2219 in the original version.
Ken
On Wed, Feb 3, 2021 at 2:07 PM Henry Spencer <hspencer@xxxxxxxxxxxxx> wrote:
On Wed, 3 Feb 2021, Brett Coles wrote:
Wouldn't you want to avoid aluminum tubing in oxygen systems since it's
flammable?
Essentially all metals are flammable in oxygen, although some are more
reluctant to ignite than others. "At Rotary Rocket, we got real tired of
proving that stainless steel burns." -- Jeff Greason. Aluminum generally
has a hard, stubborn oxide layer on its surface, and also conducts heat
away from hot spots very well, so igniting solid aluminum is actually
rather difficult.
The NASA Lewis safety manual includes aluminum and aluminum alloys in its
list of materials considered safe for low-pressure (by which they mean,
under 1000psi) oxygen systems. At high pressures the list gets much
shorter.
Henry