1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Stored Energy in a pressure vessel

  1. Jan 19, 2009 #1
    Consider a problem where a tank holds compressed natural gas, compressed to approx. 250 times atmospheric conditions.

    Now release the tank valve letting some of the gas out.

    Assuming a small timestep, I can approximate the energy lost as 1/2 mv^2,

    where m is the mass released during the timestep, and v is the (assumed constant for small timestep) velocity of exiting gas.

    Can I equate this to the change in stored energy in the tank during this timestep with reasonable accuracy?

    If so, can I model the stored energy as E = PV

    where P is pressure in the tank and V is the volume.

    Thanks alot.
     
  2. jcsd
  3. Jan 19, 2009 #2

    mgb_phys

    User Avatar
    Science Advisor
    Homework Helper

  4. Jan 19, 2009 #3
    I think the difference is that I was assuming an isochoric process, since a tank of fixed volume held the process. Maybe this is not the case? Either way, it should be noted that in my case I am just looking for a valid approximation, so I do not wish to model a differential problem. I have been using timesteps.

    So if isochoric is assumed

    Work = PdV = 0

    But I am looking at stored energy, not work done, this is where I am confused.
     
    Last edited: Jan 19, 2009
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Stored Energy in a pressure vessel
Loading...