Cryogenic System

[Fluids101]

Hello all,

I'm newer to cryogenics design, but have a few questions after reviewing some simple LN2 transfer schematics:

​

1. I know it's required to have relief valve between any two valves, but is it required to have a relief valve between a regulator and valve too?

​

2. Are accumulators used in a cryogenic system for energy storage like pneumatic, or a different purpose like vibration/shock reduction?

​

3. I'm noticing a lot of valves in parallel. Is this mostly for fast fill, chill down or replenish?


Thank you

 

[csk62]

A thermal relief is required for any trapped liquid volume scenario. Assuming a volume between a manual valve and a liquid regulator (maybe on a PB circuit) a thermal relief must be included since the regulator may close.

 

[WKTaylor]

F101...

Aircraft or Missile or ground-storage/transfer or...?

Any Cryogenic system... especially fuel/oxidizer liquids... system design, is extremely serious business.

'War-story'...

Rainy days in a row... several empty 'LOX bottles' [can't remember formal term for cryogenic liquid storage containers, right now] for a 'jet' [squadron] were filled and transported to the ramp for installation in jets, prep for mission in an open-air cart.

LOX bottles were installed by technician who 'failed' to ensure that relief valve ports on bottles and the Acft LOX compartment-vents were 'free/clear' of moisture/ice.

Yep... as bottles warmed-up in the jets, ONE of the bottles was unable to vent-off GOX... pressure built-up and about 1-hr after servicing the LOX bottle was over stressed and catastrophically ruptured... almost severing the fuselage thru the LOX compartment... major structural repair at depot was required [+2 years].



Regards, Wil Taylor

o Trust - But Verify!
o We believe to be true what we prefer to be true. [Unknown]
o For those who believe, no proof is required; for those who cannot believe, no proof is possible. [variation,Stuart Chase]
o Unfortunately, in science what You 'believe' is irrelevant. ["Orion", Homebuiltairplanes.com forum]