Contact US

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!

*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

Gas flow formula - multiple diameters of pipe in series

Gas flow formula - multiple diameters of pipe in series

Gas flow formula - multiple diameters of pipe in series


I am currently making a calculations spreadsheet for pipeline services and am thinking of how best to calculate gas flowrates. Liquid is simply the Darcy-Weisbach equation with Churchill (Darcy) Friction Factors.

However when it comes to gas, for example the dewatering of a liquid-use pipeline precommissioning, I am considering using the general gas flow formula described in "A Tutorial on Pipe Flow Equations" - Schroeder.

Currently I have five pipeline sections programmable, and a downline (hose) each could be different lengths and diameters.

Is there some form of this equation which accounts for the different sections?

If not, then I am considering setting an equivalent diameter of say 10" for example, and calculating the required length of this 10" pipe to generate the same back pressure as the original diameter and length of pipe, with the same flow rate. With all sections translated into the equivalent length of 10" pipe, then using this to calculate the required parameter. Is this acceptable?

Pipeline Services Engineer in the Oil & Gas Sector

RE: Gas flow formula - multiple diameters of pipe in series

Friction factor is a function of both Reynolds Number (which includes pipe diameter as a first order parameter) and pipe diameter over pipe roughness. Don't try to make an homogenized "average" pipe diameter. Just run your sections as independent inputs to the next step. If you have a need of precision, your 10" answer will not satisfy it. If you are looking for order-of-magnitude numbers just use a simple chart that has upstream pressure vs. dP/unit length for various pipe sizes.

David Simpson, PE
MuleShoe Engineering

In questions of science, the authority of a thousand is not worth the humble reasoning of a single individual. Galileo Galilei, Italian Physicist

RE: Gas flow formula - multiple diameters of pipe in series

Look's like I'll have to stop being and lazy and finding a work around and get coding then. Thanks alot.

Pipeline Services Engineer in the Oil & Gas Sector

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! Already a Member? Login


Low-Volume Rapid Injection Molding With 3D Printed Molds
Learn methods and guidelines for using stereolithography (SLA) 3D printed molds in the injection molding process to lower costs and lead time. Discover how this hybrid manufacturing process enables on-demand mold fabrication to quickly produce small batches of thermoplastic parts. Download Now
Design for Additive Manufacturing (DfAM)
Examine how the principles of DfAM upend many of the long-standing rules around manufacturability - allowing engineers and designers to place a part’s function at the center of their design considerations. Download Now
Taking Control of Engineering Documents
This ebook covers tips for creating and managing workflows, security best practices and protection of intellectual property, Cloud vs. on-premise software solutions, CAD file management, compliance, and more. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close