LDM Member

MFMP dogbone thermal versus applied power. A case study




In post #445 in this forum thread we have shown that for the second MFMP dogbone thermal test the applied electrical power differs largely from the calulated thermal power.
This can be possibly…

(Quote from Alan Smith)


Let me quess.

Instead of applying heat by a continuous pulse width modulated voltage to the heater coil you are now applying power in a more burst like fashion ?

(Quote from Alan Smith)

So you changed the control algorithm to incorporate the Mouse and Cat protocol ?

Radiated and convective power calculation of the MFMP Dogbone thermal simulation 500W, 700W and 900W runs.




In the attached spreadsheet the total radiated and convective power of the second MFMP dogbone thermal test was calculated.
Temperatures of the…

(Quote from Paradigmnoia)


Initially that didn't work also
If I loaded another profile then the one embedded in the Ravi file, then the colored temperature information disappeared.
Also the configuration menu was not properly working and I had many…

THHuxleynew

'm not saying you are making stuff up.




That's what Zeus46 already explained.
I think I need to fly over to Liverpool to visit family and upgrade my understanding of the English language. (Have already an invitation)


I'm saying the…

I took this horizental profile from the Ravi 500W file



And think indeed that this is a profile measured with an in band Optris emissivity setting of 1
Your picture with the different sections as in Lugano is nice and gives the average section…

(Quote from Zeus46)


Thanks for explaining the underlying meaning !

(Quote from Paradigmnoia)


The text in the report is :

We therefore took the same emissivity trend found in the literature as reference; but, by applying emissivity reference dots along the rods, we were able to adapt that curve to this specific type of…

THHuxleynew

The report says the dummy run used thermocouples for temperature (which were not used for the active runs).


You just can't make this stuff up!

Sure they used thermocouples in preparation of the dummy run.
(Actual one, the one as they…

Lugano dummy run with supposed Optris emissivity error recalculated


In the attached Excel spreadsheet the total radiated and convective power of the Lugano test for the situation in which the Lugano testers would have used broadband instead of…

Nice work !

From which MFMP test did you use the Ravi data ?
The 700 Watt or 900 Watt run ?

The minimum temperature set for the color display was somewhat high in the MFMP Ravi file and as such the cap temperatures where a flat profile showing the…

(Quote from Paradigmnoia)


That one I didn't know !

Thank's for the link

Chapter 11 (from link below) has some handy calculations and a cool table of BB radiation functions (page 570, PDF page 10)

http://mechfamilyhu.net/downlo…ss.Trafer%20by%20chapter/

(Quote from Paradigmnoia)


Thank's for your checking that theory and practice are about in line, at least for the lower temperatures.

Really appreciate it because I was not sure if we where overlooking something.


What I do not understand is how Optris…

Recalculated Lugano temperatures when temperatures where inflated

In post #406 the formula to be used for recalculating temperatures between two emissivity value settings on the Optris thermal camera has been established.
The factor n needed in that…

Recalculating inflated temperatures when wrong emissivites where used- Determining n


Inresponse to my previous post on the subject THH correctly mentioned that the factor n, used in the Optris forumla (see previous post #406) is as he stated highly…

THHuxleynew  


Thanks again

I wrote in the past already a VB program which integrates the Planck function over a bandwith range.
Will play with it or adapt it to find n for the Optris band as a function of the temperature

(Quote from LDM)


You can do a numerical integration of the Planck curve spectral power over the camera frequency passband, and note how that changes with T. Specifically Accuracy would require knowing the Optris spectral response which may be difficult…

(Quote from THHuxleynew)


Thanks THH,


Will investigate this further.

If you have more info how to calculate n, then I would be gratefull to receive it