Thermowell vibration analysis 2

[dfdz]

Hi everybody!
Is there any limit in flow speed above which you must analyse vibration influence and below it you don´t need to?
In case there is a limit, how do you determine it?
Thanks in advance.
DFDZ

 

[DRWeig]

dfdz,

Yes, there are bad ranges of flow for almost any shape thermowell. There's the possibility of resonance. I'm not good at the analysis, though, but here are some docs I keep for disccussion.

http://www.temperatures.com/twellwakes.html

http://tappi.micronexx.com/JOURNALS/PDFS/02APR10.pdf

Good on ya,

Goober Dave

 

[danw2]

I don't know the answer to your question, but I do have a copy of WellStress that runs some numbers on thermowells. Not bad for a freebie.

The software author's name and email address is on the download site. An email to him might provide a rule-ot-thumb answer. If you try him and get an answer, it would be nice to know it.

http://www.tempsensor.net/index.php?name=Downloads&req=viewdownloaddetails&lid=13

 

[dfdz]

Thank you all.
Both comments were very helpful.
I will study the docs and I´ll be back with my comments.
DFDZ

 

[temperaturetalk]

Since this post was first made the ASME PTC 19.3 TW (2010) standard has been published and significantly changed the standard means of assessing wake frequency / vibration issues.

As a thermowell and sensor manufacturer hoping that we could help users like you, we built a free software application to run the new standard. Here's a link:

http://www.jms-se.com/swiftycalc

 

[DRWeig]

Nicely done, temperaturetalk!!

Good on ya,

Goober Dave

 

[dfdz]

Very nice really. Thanks a lot.
DFDZ

 

[temperaturetalk]

You're welcome! Good to hear yr feedback.

 

[jmw]

I just spotted a similar interest at Control.com and remembered this thread.
It appears (courtesy Frank Johnson at Control.com) that:

ASME PTC 19.3 TW 2010 has been published and is now available at

http://www.ASME.org.

This is a total rewrite of the calculations used to determine the wake frequency for thermowells in a flowing process.

and Frank goes on to suggest SwiftyCalc which is here:

http://www.jms-se.com/Apps/Tools/ThermowellDesign/Home.aspx

JMW

http://www.ViscoAnalyser.com

 

[DRWeig]

I just want to throw in that SwiftyCalc RULES!!

Somebody did a super job with that one.

Good on y'all,

Goober Dave