Vibration detection for blades in turbo machinary 1

[gordonl]

This is also posted in "Mechanical - Vibration" Forum, but thought I would post here since motor experts are often also the vibration experts:

I'm looking at reusing the existing proximity sensors on a steam turbine driven axial compressor for a new monitoring system. There are 4 sets of x-y probes, one set on each bearing, a thrust probe, and a key way probe for speed and phase. Is there any value in having accelerometers added to the cases of the machines?

The system:
- 3800rpm
- 30,000 BHP
- Journal Bearings
- Existing pickup IRD Mod 403 with IRD Mod 14538 Signal sensor
Turbine:
- 700lbs steam
- 27 stage
Axial Compressor:
- 175,000SCFM of air at 15psia
- 13 stage with variable stator vanes

I've seen suggestions that if blade problems are going to be detected accelerometers are required.

Questions restated:
- What types of blade problems can be detected?
- What freq response is required from the system?
- Would one accelerometer on the machine case be enough?
- Should I worry about turbine and compressor or only compressor?
- Any other comments or life experience.

Thank You in Advance,
Gord

 

[ScottyUK]

gordonl,

Try contacting either Bently Nevada or CSI (part of the Emerson Group). Both companies have condition monitoring systems that they have been marketing quite aggressively. Their applications engineers (they were salesmen when I was a kid...) will almost certainly prove to be a goldmine of information, and their websites are quite informative.

Our site has a large amount of B-N gear installed, and it has proved to be pretty good from a reliability point of view.

Hope this helps.





-----------------------------------

Start each new day with a smile.

Get it over with.

 

[jbartos]

Suggestion: Visit

http://www.plantservices.com/web_first/ps.nsf/ArticleID/CBOH-5M5QQD?OpenDocument&Click=

http://lmh

http://www.epfl.ch/Publications/Public.pdf/CAVIPU_012.pdf

http://cav2003.me.es.osaka-u.ac.jp/Cav2003/Papers/Cav03-OS-6-007.pdf

http://www-staff.lboro.ac.uk/~mcbjh/papers/Turbomachinery_Blade_Vibration_Analysis.pdf

etc. for somewhat related links and info
Questions restated:
- What types of blade problems can be detected?
///Any mass deviation from the designed physical locations.\\- What freq response is required from the system?
///Any asymmetry in the frequency responses will indicate degradation in the blade structure and geometry.\\- Would one accelerometer on the machine case be enough?
///It depends on the measuring techniques and sought observations.\\- Should I worry about turbine and compressor or only compressor?
///Turbine is generally more likely to experience degradation; however, the set is to be analyzed globally.\\- Any other comments or life experience.
///This is a mechanical/dynamics issue. There are various resonances due to vibration possible. Post this also under mechanical engineers in this Forum.\\\

 

[gordonl]

John,

Thanks for the links, after a bit of panning I pulled out a few gold nuggets.