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Lugano Thermal Assessment Take 2

Written by Robert Greenyer on .

Our last and best []=Dog Bone=[] is preparing for another verification of the Lugano report.
 
 
In order to resolve some nagging questions in the community and because we are really the only people that are in a position to do this, we are revisiting this controversial area to settle remaining doubts.
 
Better power analyser and better metrics are in order, same PI160, lens and calibrations as Lugano. All temperatures in ºC
 
 
Huge thanks to the team, especially Alan and Skip for agreeing to spend their time doing this. Some set up will need to occur before this happens, but with Brian Albiston's fantastic recent contribution, this is made a lot easier.
 
Thanks must also again go to Ryan and Paul Hunt at HUG for making the []=dog bone=[] and to BobCat Sweden for paying for the repair to the Optris.
 
Proposed layout below (the C.xx area has been set to average in the above downloadable layout file)

Reflecting on the original tests and our experience since - a few potential things need to be resolved.
  1. Blocking the ends of the reactor tube rather than having them open as in the case of the first verification
  2. In the first tests, we established by way of the Williamson IR 3mm spot that the average of the top third of the ridges was 100ºC hotter than the same span in the crevice. This meant that the K-Type and B-Type TCs, which had end beads of differing sizes, read slightly differently in the original tests.
  3. The original TCs were held in place by fine Kathal wire and so were partially in convective flow - in this case they are bonded to the surface, leveraging the TC bonding experience we have gained since.
In this test, the high emissivity paint (1 at 800ºC) is in a flat area and the comparative adjascent alumina has been flattened also - this should remove the ridge/crevice issue from the original tests and provide a bullet proof calibration as per the Optris manual.

More details and a quick RAVI (Radio Metric AVI) file to download so you can learn to play with the set-up
 
https://goo.gl/NSZYMD

If you have a windows PC, you can download the free Optris PI-Connect, load the sample RAVI from the set up and import the Layout - with this, you can play with the regions and emissivity to your hearts content and be ready for a similar file we intend to share after the main test.

Comments   

 
0 #4 charlie tapp 2017-03-12 21:47
I don't quite understand what is going on mfmp has not openly distanced themselves from recent on goings and seems strange that that stuff keeps popping up on mfmp Facebook page. Is bob the one that runs this web site and the Facebook sight? Is mfmp done now please we need some idea of what the hell is going on
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0 #3 DAK 2017-03-11 16:51
Having a ramp-up and ramp-down temperature measurement by both the Optris and thermocouples would be helpful. In that manner you could see if emissivity varied with temperature and the rate of warm-up and cool-down. In this case, you would need to increase the Optris data acquisition to gather data faster. Whereas, at steady-state once every 5 mins would likely be too much data. Once every 10 secs may be too slow. This data was missing from Lugano?
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0 #2 DAk 2017-03-10 21:28
I am glad that you agreed to repeat this test.
To the extent that you are mimicking Lugano, the most important result is the power-in vs. the APPARENT temperature as measured with the Optris system set on an emissivity of whatever you think was used in Lugano. The actual temperature is immaterial. It would be helpful to remain at a given power input for an extended period of time and vary conditions at that power input. For example, the effect of air flow - say nothing but "normal" convection vs. several known air flows. These changes should be evident in the temperature. Going to and maybe 10% above the purported Lugano power input would be helpful.

This will immediately collaborate or refute the Lugano data set. There is no need for complicated modeling nor arguments over emissivity vs. real temperatures.

Now you can go wrong if your set-up does not adequately mimic Lugano. Conduction through the ends may be different. Or, your material or casting may have different surface area. It would be nice to know the effects of these types of variables. However, if these variables matter that much, then modeling with inadequate data would not be helpful.

Why the air flow? Say Dr R. had a door open during the control and the airflow in the room was different that during the actual test. Measuring if air flow matters substantially would discount such trivial (but actually hard to detect) issues. At the alleged temperature, emission should be dominate but that assumes certain conditions - air flow and conduction being a certain way.

I look forward to your results! The more you vary the experiment around some of the above parameters, the better will be in the confidence that you nailed Lugano.
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0 #1 L. Tijben 2017-03-01 16:21
I would propose to mount thermocouples in line with the body, then let the thermocouple wires run for a short distance on the body before running them off perpendicular to the body.
In that way less heat is drained from the thermocouple tip and the temperature readout will thus be closer to the real temperature
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