potential energy of a compressed gas
potential energy of a compressed gas
(OP)
All:
I have been asked to assist with reworking the projectile calculations guideline for my company. We perform a significant number of high pressure hydrostatic and gas tests of pressure containing equipment.
I would like to request assistance from compression experts to assist me in determining the stored energy in a pressure containing equipment piece when I know the following variables:
1) test medium = N2 nitrogen gas
2) test pressures = 5-15 ksig
3) test volume = can be accurately determined for each test
4) test temperature = 50-70 deg F
All gas tests are performed in a water filled pit for leak observation and safety purposes.
If members can help me in determining the stored potential energy, I feel I'll be on my way. I can handle the kinematic and water drag equations once the projectile is launched, although I hope this never happens.
Thank you.
I have been asked to assist with reworking the projectile calculations guideline for my company. We perform a significant number of high pressure hydrostatic and gas tests of pressure containing equipment.
I would like to request assistance from compression experts to assist me in determining the stored energy in a pressure containing equipment piece when I know the following variables:
1) test medium = N2 nitrogen gas
2) test pressures = 5-15 ksig
3) test volume = can be accurately determined for each test
4) test temperature = 50-70 deg F
All gas tests are performed in a water filled pit for leak observation and safety purposes.
If members can help me in determining the stored potential energy, I feel I'll be on my way. I can handle the kinematic and water drag equations once the projectile is launched, although I hope this never happens.
Thank you.





RE: potential energy of a compressed gas
So determine your internal energy at pressure (specific internal energy knowing P and T and then multiplied by mass) and then again assuming it isentropically expands to atmospheric pressure. The difference is the amount of energy released.
RE: potential energy of a compressed gas
Stored energy = Gas pressure X Tank volume.
This is the energy released when the tank bursts. Sometimes it is converted to the weight of TNT bomb explosion.
RE: potential energy of a compressed gas
David Simpson, PE
MuleShoe Engineering
www.muleshoe-eng.com
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
The harder I work, the luckier I seem
RE: potential energy of a compressed gas
It seems then there is no tried and true method, theoretical or empirical, for estimating stored energy due to gas compression in a pressure containing piece of equipment.
Is this what I am hearing from the group?
I'm dealing with volumes in the 20,000 in3 to 2 in3 range depending on the size of and component(s) being tested.
RE: potential energy of a compressed gas
1-chemical energy,
2-potential energy (due to gravity ie, elevation),
3-internal energy ( U=mu, where m= mass and specific internal energy ie,similar to Cv*T for perfect gas)
and
4-kinetic, if vessel is moving,
Note for internal energy of perfect gas, kinetic energy of molecules defines temperature.
Regards
Regards
RE: potential energy of a compressed gas
On page 10 there is a table of stored energy up to 30000psi per volume of 1 cubic feet.
RE: potential energy of a compressed gas
good luck!
-pmover
RE: potential energy of a compressed gas
This item has been discussed in other forums. Following iainuts' message, the energy, expressed in liter-atm, that could be released in an adiabatic expansion (i.e., explosion) of an ideal gas equals
where
p1 is the test pressure, atm
p2=1, atmospheric pressure
V =volume of vessel, L
γ = 1.4 for nitrogen