×
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 in LPG lines

pressure drop in LPG lines

pressure drop in LPG lines

(OP)
what formula and friction factors is applicable when you want to determine the pressure drop in LPG lines?

thks

RE: pressure drop in LPG lines

Use Darcy (or Fanning whatever name you prefer). LPG is a single phase fluid and behaves quite normally.

Best regards

Morten

RE: pressure drop in LPG lines

(OP)
Thks Morten

But what if vaporised LPG is to be piped?

RE: pressure drop in LPG lines

If this is going to an appliance like a boiler or furnace, then typically there are jurisdictional fuel utilization codes that specify (among many other things) line sizes for various loads, equivalent length of piping run and inlet pressures. Any of the ones I've seen are tables included in the applicable code book. You'll likely save yourself a lot of grief from the local inspection authority if you just go with the pipe size shown.

RE: pressure drop in LPG lines

mechanicaldup:

When you mention a fluid to transport, you should identify its phase.  There's a difference.  Just like there is a difference between the Fanning Equation and the Darcy-Weisbach Equation (the Darcy friction factor = 4 x Fanning FF).  If you are handling a gas or vapor instead of a liquid, the same basic Darcy-Weisbach relationship can be employed if the pressure drop is less than 10% of the initial pressure.  This is to stay within reasonable accuracy.  If you're handling a mixed, 2-phase fluid then you've got a worse problem.  It gets really sticky and inaccurate.

Vaporized LPG is calculated for pressure drop just like any other pure vapor - with an appropriate gaseous calculation equation.  Or, if the pressure drop is less than 10%, then you can use the D-W equation with reasonable accuracy.  Otherwise, use an appropriate gas computer program or spreadsheet to calculate the pressure drop.

RE: pressure drop in LPG lines

Allright Art - yes theres a difference between Fanning and Darcy - i just assumed that people wathing these page would either check or know...

Apart from that i agree with your comments re. knowing wich phase your dealing with is important and if there is a phase trancition and that multiphase is nmore difficult than single phase (at least for hand calc. allthough it take the same time when using a suited simulation tool).

Best regards

Morten

RE: pressure drop in LPG lines

As long as the pressure drop is a within normal range the normal 'incompressible flow' formula can be used.
Try www.engineeringpage.com - the pressure drop routines will do the calculation work for you

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