×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Pressure drop at pipe damage

Pressure drop at pipe damage

Pressure drop at pipe damage

(OP)
Is there any resource how to estimate preasure drop when gas line gets some damage (hole, pinhole, gilotine, large hole) ?

Ex.
Pipe line with natural gas at 30 bar. Length cca 10 km.
Which hole size is neccesery to have preassure drop of 1 bar/min.
Or vice versa: for some hole (type) how much is pressure drop.

RE: Pressure drop at pipe damage

(OP)
Diameter of pipe in example above should be 20"

RE: Pressure drop at pipe damage

The easy way is to assume the pipe is a closed container with Vol = pipe segment volume, Pressure = P1, Temp = T1.
Decrease the volume by a given amount, dV
Calculate the new pressure using P2=ZRT2/T1/(V1-dV)
That's the pressure drop you will experience over the time it takes to lose volume dV.  If the line is flowing, you will have to add the gas going into the segment and subtract the gas leaving the segment.

You can then correlate that leak flowrate to an equivalent hole diameter using a thorough an orifice equation with P2 on the inside and atmospheric pressure on the outside.

The easier way is to use a gas transient program and simulate various leak rates and watch the actual pressure drops you'll get for each one.

   Going the Big Inch! worm
http://virtualpipeline.spaces.msn.com

RE: Pressure drop at pipe damage

(OP)
Thank You for reply BigInch.

The first part I understand.

The other part with "equivalent hole diameter" and "orifice equation" I have problem right now. Can You point me on some page or other resource (not paper books) for help on this calculations.

Or even better, "gas transient program" recomendation (possibly small for donwload).

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources