Southampton PA, USA — Through the courtesy of Dr. David Bartran we have been making available his free thermowell vibration modeling software, WELLSTR for the engineering and scientific community at large.
The latest version WELLSTRv7, was just provided after feedback from one of our users. It is available for download by registered users at TempSensor.net in the download section of the website. Of course, there is no cost to register. That requirement is to minimize content spam. All you need is a valid email address and the time to share it with us. We respect your privacy; our policy is clear and simple.
Among his comments on the new version Dr. Bartran says the following:
“Added arbitrary liquid for those who might find it useful, and added a column in the output file (WellStr2.txt) that list tip acceleration stress.
“The latter is particularly important in the case of RTDs. I try to keep the tip accelerations less than 5G for Pt Rtd’s and less than 10 Gs for thermocouples.When the tip accelerations exceed 10-20 g’s, the sensor literally jack hammers itself to pieces inside the well.
“RtTDs can also experience decalibration under severe vibration. This is
observed in pump delta-temperature measurements and can be a serious issue.
“At least one vendor offers special sensor assemblies for high vibration services.
“When using the wellstr code for the case of an arbitrary fluid, it asks for the thermodynamic properties. If you don’t have reasonable estimates,
then you can enter nominal values or just the numeral “1″. Of course the measurement error calculations will no longer be valid. When you use the mass flow just enter the flowing sp. gravity for the two sp. gravity entries the code asks for. The standard gravity is only useful when volumetric flows at standard conditions are used. “
NOT FOR NEWBIES!!!
USERS AGREE TO ASSUME ALL RESONSIBILITIES FOR ANY UNINTENDED CONSEQUENCES WHEN THEY DOWNLOAD.
(NOTE: THIS VERSION IS IN COMPRESSED, ZIP FORMAT. That helps keep the download reasonable. The unzipped version is over 270 Kb, while the zipped one is about 86 Kb. That can mean a lot to someone with a 12 kb modem; they still exist! There are several free and low cost programs with free demos on the Web that can extract the .exe file from the compressed form such as those found on www.winzip.com and www.pkware.com).
If you are unable to access the files for download or extraction of the the executable program from the compressed format, drop me an email at grpeacock at tempsensor.net, and we will do our best to help you get what you seek.
To Learn More
Thermowells are subject to more than just the static forces from the fluids going past. They also can have vibrations induced from the fluid vortices in the wakes (the von Karman wakes) created by the interaction between them and the fluids. This has been known for a very long time and it is most significant in the realm of highly energetic flows.
The induced vibrations are very critical when their frequency corresponds to the resonance frequency of a thermowell . Under such conditions, the temperature sensors can literally be pounded to pieces. The thermowells themselves can rupture in extreme cases.
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