×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

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

vibration in pipelines

vibration in pipelines

vibration in pipelines

(OP)
Is there an equation/method for determiining the maximum velocity/flow rate  of fluid in pipeline before vibration begins?

RE: vibration in pipelines

No. The pipeline vibration also depends upon pipe support, etc.

RE: vibration in pipelines

Above 3 m/s flow speed is a general value were Reynolds number is going bad. But not only the flow speed can produce bad effects. Is more common to find vibration problems by other causes, and most deal with non steady conditions.

In most cases what you have to do is to design a pipe line which has a natural frecuency higher than any spected excitation frecuency. (In other words, a system with vibration sources that would not be close to those that may produce a bad "vibrational" response).

As a rule of thumb, for a well supported steel pipe (following ASME B31 code design criteria for example, with tipical geometries on a plane), excitation frecuencies higher than 30 Hz would not be dangerous (i.e. a fatigue problem would be hardly met).

RE: vibration in pipelines

(OP)
Thanks for that,  I have, however, seen rules where for a given density x velocity squared value a maxium flow rate is given.  Is this an in house rule of thumb or a more established corelation?

Daniel

RE: vibration in pipelines

Several thing will cause vibration of a piping system:
1) bad support system
2) improper support of piping connected to recipricating equipment
3) Slug flow, also known as two phase flow
4) water hammer

Velocity by inself is not going to be a problem. If you have a system that is vibrating it can usally be traced back to one of these four.

EEG

RE: vibration in pipelines

I think that the formula you are looking for is in API 14E which gives a formula for erosion velocity which is a constant divided by the square root of the density.

RE: vibration in pipelines

The liquid speed in a pipeline doesn’t produce pipe vibration by itself, it would be rather the rate of change of such speed that will possibly cause it. 3 meter per second maximum, also DavidCR suggests, is the limit for a good design in that, as much is your speed as much your system instability will increase such rate of change. Change of speed, anyway, affects the most the water hammer phenomena, with an over pressure that could burst your pipe. Two phase flow in some case causes cavitation and consequent vibration, but in this case the problem is it could seriously damage and disrupt your pipe.

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


Resources

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