Projectile Velocity from Pneumatic Test 1

[The Iceman]

Hi All,
I am trying to design a pneumatic testing bay and want to make sure it will be robust enough.

Need some help determining worst case velocity of a projectile in case of a failure. My projected worst case is if one of the fittings fails and comes shooting out.(the tank is overdesigned and should handle the pressure)

My approach was to calculate the overall stored energy in the vessel using the Baker Equation. I figure that would be worst case and if I take that energy and convert it to Kinetic Energy of a potential projectile I can calculate the worst case velocity of that projectile. Basically PE=KE=(1/2 mass(of the projectile) times V²) and just solve for V

Does that all make sense? I am getting some awfully high numbers for possible velocities of a fairly light projectile.

Someone suggested I use the mass of the overall pressurized unit as the mass in the KE equation. In that case I could just weld some heavy weight to the outside of the unit and that would slow the projectile significantly. I can see that slowing the pressure tank's movement but not a fitting that were to fail and come shooting out.

Thoughts on this or do you have a completely different method of determining a worst case velocity?

 

[rb1957]

that sounds like safety of the entire tank, not something getting expelled from it.

I don't know if Ed's "experiment" (fun tho' it may be !) is directly applicable. I had thought of the gun idea, but I re-read the OP as saying he has a fitting on the outside of the tank and suddenly it lets go of the tank. If that is the case, then maybe more likely (than the fitting flying off the tank) is that the fitting flange leaks and the tank decompresses ?

"Hoffen wir mal, dass alles gut geht !"
General Paulus, Nov 1942, outside Stalingrad after the launch of Operation Uranus.

 

[btrueblood]

The opposite case to the one in the OP description, is to treat the remaining bottle that the projectile is launched from, as itself a free projectile aka a rocket...

vis

https://www.youtube.com/watch?v=ejEJGNLTo84

 

[LittleInch]

Iceman,

what are thinking of making this test bay of?

Steel? concrete? cardboard?

Does it has a roof / labyrinth entrance way to prevent any projectile from exiting the bay?

How do you allow enough venting in the event of a catastrophic breakage? This maybe a much larger overall force than a single item of equipment hitting a wall or roof.
You might say the tank is over designed, but nonce you have a bay then someone will use it to pressure test a vessel. The whole purpose is to test the items - sometimes tests result in failure, that's the whole point of them.
If it's open top how do you stop things flying out like a mortar?

So maybe this isn't your design case?

would be interested to know - really.



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