Rossi Lugano/early demo's revisited. (technical)

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    Or zirconia emissivity due to the Pyro Paint 634-ZO?


    Let us be more precise: of the painted alumina surface. Which might have properties (at different wavelengths) determined primarily by the paint or the alumina according to how much the paint at that wavelength is translucent.

  • Let us be more precise: of the painted alumina surface. Which might have properties (at different wavelengths) determined primarily by the paint or the alumina according to how much the paint at that wavelength is translucent.

    I think that as far as the Optris is concerned there isn't much difference with or without the ZO paint.

    Total emissivity might vary a bit.

  • Is that the Lugano Plot 1 alumina E vs T curve on there? I haven’t seen much evidence for that that little drop in E at the low T end of the plot.

  • Is that the Lugano Plot 1 alumina E vs T curve on there? I haven’t seen much evidence for that that little drop in E at the low T end of the plot.


    Note that my plot starts at 220 degree C instead of 0 degree C in the published plot 1 of the Lugano report.

    The Alumina emissivity values I used are the digitized ones from the MFMP.

  • Note that my plot starts at 220 degree C instead of 0 degree C in the published plot 1 of the Lugano report.

    The Alumina emissivity values I used are the digitized ones from the MFMP.

    It is good to be consistently comparing to the same data.


    However, consider the low temperature range in this overlay plot containing multiple Al2O3 emissivity vs temperature data points. (Blue line is from Lugano Plot 1)


    8473-alumina-e-overlay-plot-1-v2-jpg

  • It is good to be consistently comparing to the same data.


    However, consider the low temperature range in this overlay plot containing multiple Al2O3 emissivity vs temperature data points. (Blue line is from Lugano Plot 1)


    8473-alumina-e-overlay-plot-1-v2-jpg


    I'm not certain - but those 300 and 450 points look as though they may have been book total emissivity corrected according to empirically determined band emissivity (remember the authors of the paper did not admit any difference between the two!).

  • I'm not certain - but those 300 and 450 points look as though they may have been book total emissivity corrected according to empirically determined band emissivity (remember the authors of the paper did not admit any difference between the two!).

    The plot points look like the ones they gathered from emissivity reports listed, so I see no evidence of the emissivity having been adjusted.

  • It is good to be consistently comparing to the same data.


    When I made the plot some time ago, I was not interested in the low values

    So the plot was not made to be an exact match with the Lugano data range.

    But it is the same data for the temperature range shown.



    However, consider the low temperature range in this overlay plot containing multiple Al2O3 emissivity vs temperature data points. (Blue line is from Lugano Plot 1)


    That plot is the same as published in :


    HANDBOOK OF THE INFRARED OPTICAL PROPERTIES OF AI2O3,

    CARBON, MGO, AND ZRO2. VOLUME 1


    Note from the reference on page II-4 in that handbook what kind of samples where tested and included in the plot :


    Spectral Emittance and reflectance of Powders, Powder on metalic substrate, Condensed Oxides on sollid Propellant Combustions products, refractory materials, ....


    With al those physical differences in samples, you will indeed get a very deverse plot.



    I once compared the Lugano plot with NASA data for solid Alumina which showed that from 500 degree up, the Lugano plot has almost identical values as those measured and published by NASA.

    This has given me some confidence that at least in that range the values must be correct.


    Also the COP values you calculated for your rod measurements at different temperatures are about 1, which means that the Lugano emissivities you used must be about correct. (At least for the Durapot)





  • The Lugano iteration procedure ?


    In the attachment to this post a procedure is presented which can be used in combination with the Optris to find the temperature and emissivity (for Alumina).

    It includes an iteration procedure outside the Optris.

    When the dummy run of the Lugano report is recalculed using the method presented, then the initial temperature to be used by the iteration procedure, the intermediate values of the iteration and the final temperature obtained have values close to those presented in the Lugano report.

    Using a MFMP ravi file the procedure is also checked for higher temperatures then used during the Lugano dummy run. The conclusion is that at higher temperatures the results are still accurate.

    The procedure also shows that the temperatures can be accurately measured without calibrating the Optris. Also the procedure uses only information from the Alumina broadband emissivity curve during the iteration.

    Since the recalculated data for the dummy run iteration is in close agreement with the values presented in the Lugano report, the presented procedure might have been the one used by the Lugano team.

    It is however no proof that this indeed the case but shows that such a procedure outside the Optris is at least possible.

  • I was agreeing that it is good to use the same data set.


    The alumina curve the Professors used does seem to be pretty good, overall, based on my testing. But it was as much luck as skill that they used that particular data set to base their calculations on. Because they did not calibrate with the alumina they used, the Professors had no idea how valid the alumina emissivity data they used was. This is because they tested a Rod, which they themselves described as being of a different fineness and manufacture than the Rib area.

  • The Professors (at least some of them) tested alumina emissivity and are well aware of the temperature error made in the Lugano report.


    Of course there are cool other ways to work out the in band emissivity if one has the skills, patience and desire. However, it is certain that the Professors used the method explicitly described in the report in over one page of writing and tables, and reported elsewhere in the report that they used that method, as described, for the entire set of calculations. No point pretending otherwise. Ask the Professors what they did, if in doubt of the methods used.

  • it is certain that the Professors used the method explicitly described in the report in over one page of writing and tables

    It was explicitely stated in the report that assigning an emissivity of 1 a temperature of 366.6 degree C was obtained. (Table 2a)


    However if we assume a non inflated temperature of 450.3 degree C, then setting back the emissivity to 1 would have resulted in a temperature of 420.9 degree C.


    if we take the text explicitly and assume that broad band emisivities where used on the Optris, , then the real temperature would have been 377 degree C.

    If that was the real temperature, then for an emissivity setting of 1 the Optris would have shown a temperature of 342 degree C.


    The conclusion is then that the method explicitly described by the Lugano team is not in agreement with the data published.

    This means that or the published data is wrong or their method is not explicitly described.


    Take your choise.



  • The report claims that a rib from the reactor body was tested and was >99% alumina, when the Rib area was, according to IH representatives that were aware of its construction because they made it (and included the details in a patent application) said it was made of Durapot 810 which is 75 to 85 % alumina plus other undisclosed ingredients, plus that it was painted with zirconia paint that Fabiani reported the paint manufacturer model number of (Pyro Paint 634-ZO).


    So was it pure alumina, Durapot, or something else, painted or not painted?

    Mix or match with your choice.

  • Lugano dummy run recalculation for Zirconia coated ECAT


    As Para already stated in an earlier post, there will be not much difference in measured temperatures between Alumia and Zirconia as far as the Optris is concerned.

    This makes it possible, using the published temperatures in the Lugano report, to calculate approximately the total convective and radiated power if the Lugano ECAT was coated with Zirconia.

    The attached Excel file shows this calculation.


    Since for dummy run temperatures the broad band emissivity of Zirconia is lower the the emissivity of Alumina, the radiated power must also be lower.

    A calculation shows that the total radiated and convective power for the ECAT inclusive rods is 429.8 Watt versus 479.7 Watt applied power. (See attached zip file with Excell sheet for the calculation)

    The difference is - 10% .


    For the ribbed section the total power in case of Zirconia is 243 Watt while for Alumina the calculated power of the central section was 282 Watt.

    The difference for the ribbed section is thus about -14%.

    Also the 243 Watt is not in line with the the about 290 Watt dissipated by the heater coil in the ribbed section.


    The conclusion from the recalculation is then that is seems unlikely that the Lugano ECAt was coated with Zirconia.

    This conclusion is in line with the sample x ray christallography analysis which showed no traces of Zirconia peaks on positions 28 and 32, the main peaks for Zirconia.




  • The X-ray crystallography analysis shows no traces of anything other than alumina, therefore it was not the reactor body (Ribs area) that was tested, because the reactor body composition is far less than 100% alumina, whether it was painted or not.

  • The X-ray crystallography analysis shows no traces of anything other than alumina, therefore it was not the reactor body (Ribs area) that was tested, because the reactor body composition is far less than 100% alumina, whether it was painted or not.


    Concerning the iteration method you claim that this was done with broadband emissivities on the Optris because it is so written in the report.

    (We have in your opinion to take the report literally in that case)


    Also in the report was written that the sample was taken from the ribs and showed a composition of 99.9% Alumina.

    But now that this is contrary to what you believe, we have not to believe what is written in the report ?


    Shall we then agree that statements in the report may be incorrect, both for the iteration and where the sample was taken ?


  • LDM:


    There is evidence throughout the report that total emissivities were considered. Further, Levi in reply to Mats questions, vociferously defended the use of a single (total) emissivity with the Optris in determining temperature. You will also remember a Levi-proxy on here doing the same thing. At length.


    It just beggars belief for this not to have been used. The report is very very clear on the exact algorithm, showing an example.


    Whereas exactly which bit of the apparatus was tested is the sort of thing that could be gotten wrong quite easily.


    THH

  • There is evidence throughout the report that total emissivities were considered. Further, Levi in reply to Mats questions, vociferously defended the use of a single (total) emissivity with the Optris in determining temperature. You will also remember a Levi-proxy on here doing the same thing. At length.


    It just beggars belief for this not to have been used. The report is very very clear on the exact algorithm, showing an example.


    It is not based on believe, but on the outcome of calculations.


    For example, assuming that inflated temperatures where used on the Optris, then you can calculate that setting back the emissivity to 1 should have resulted in a temperature of 342 degree C, not the 366.6 degree C which is mentioned in the report.


    Also it was shown in post #548 that iterating to the end temperature on the Optris does not result in the shown iteration temperatures presented in the report.


    In adition to this all other calculations presented in my different posts have shown that the use of total emissivities on the Optris is in disagreement with the results of those calculations.

    As you state, the report shows an example, but the results of that example are not in agreement with the physical laws when one considers the use of broadband emissivities on the Optris.


    So one can hardly maintain that total emissivities where used ON THE OPTRIS.

    However I showed in post #711 that total emissivities can be used WITH THE OPTRIS.

    A small but significant difference which is in line with your statement above that Levi defended the use of a single (total) emissivity with the Optris.


    Thus total emissivities where indeed considered ! (but in a different way)