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

Sub vibration Turbo Expander/compressor

Sub vibration Turbo Expander/compressor

Sub vibration Turbo Expander/compressor

I have just started to monitor a Turbo Expander/compressor and discovered sub vibrations on the expander side. The sub vibrations does not vary with load, varies between 0.1 to 0.65 x rpm. Sometimes the amplitude is grater than 100% of 1 x rpm
I do not thik its caused by oil whirl since the viscoity is acceptable and steady. Also the bearing temperatures are fine. The overall vibration leves on the expander are approx 20 um pp.

Anybody knows whats causing the sub vibrations?

RE: Sub vibration Turbo Expander/compressor


RE: Sub vibration Turbo Expander/compressor

This kind of feels like an process side instability. Process fluid in circulation around the back of the wheel or shaft. What is the rotor configuration?

What is the fluid? Is this a cryogenic service? Can you get data as a function of load or speed? What is the speed?

20 micron on the high speed expanders I have messed with would be considered pretty high vibration.

"Why don't you knock it off with them negative waves? Why don't you dig how beautiful it is out here? Why don't you say something righteous and hopeful for a change?" Oddball, "Kelly's Heros" 1970

Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of the Eng-Tips Forums.


RE: Sub vibration Turbo Expander/compressor

The shaft configuration is "warm" turbo expander --> copling --> compressor.

The gas runs through two of these machine trains.

The system like this: Dry natural "raw" gas goes through expander 1, enters a separator and a heater. Separates again, then through expander 2. Then separates again before going though both compressors.

Running speed is approx 11000 rpm


RE: Sub vibration Turbo Expander/compressor

Futher question, what are the inlet guide vanes controled by.  There could be a process coupling causeing the two units to harmonize at a low frequency.

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


eBook - Integrating the Engineering Ecosystem
Aras Innovator provides multiple options for integrating data between systems, depending on the scenario. Utilizing the right approach to meet specific business requirements is vital. These needs range from authoring tools, federating data from various and dissimilar databases, and triggering processes and workflows. Download Now
Research Report - Simulation-Driven Design for SOLIDWORKS Users
In this engineering.com research report, we discuss the rising role of simulation and the paradigm shift commonly called the democratization of simulation. In particular, we focus on how SOLIDWORKS users can take advantage of simulation-driven design through two analysis tools: SOLIDWORKS Simulation and 3DEXPERIENCE WORKS. Download Now
White Paper - Industry 4.0 and the Future of Engineering Education
With industries becoming more automated, more tech-driven and more complex, engineers need to keep their skills and knowledge up to date in order to stay on top of this wave—and to be prepared for the Industry 4.0 future. The University of Cincinnati offers two online Master of Engineering degree programs designed specifically for practicing engineers. 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