Posts by Paradigmnoia

    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.

    Don't forget, as the Lugano paper stated, that the values of emissivity used for alumina in the iterative calculation were adjusted to make the results of that match the TC measurement. Since those values were not used anywhere else (the active test is at much higher temperatures) the IR tests during the dummy measurements are essentially irrelevant, giving no extra information. I guess you could work back from their incorrect method to the actual band emissivity of the alumina at those lower temperatures?

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

    LDM ,

    I suggest asking the Professors how the Dummy was tested with IR, thermocouples and E Dots.

    Experience suggests that questions that are not asking for an opinion on the device or Rossi, or using blaming language, sometimes get answered. The trick is to ask a question that is strictly a mechanical or scientific question.


    (Note that the Kapton-TiO2 calibrated 0.95 emissivity stickers are only good to about 380 C, whereupon the glue fails.)

    Actually the boiling point of nickel will be much lower in a strong vacuum.

    Roughly 1800 C at 100 Pa, I think.

    I don’t follow where 8 windings under the Ribs comes from. There should be 3 x 9.5 wraps under the ribs, based on the original patent application drawing.

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    727-lugano-device-lead-wires-jpg

    I read seven dots..one at centre, two at 1 cm from centre, two at 2cm from centre, 2 at 3cm from centre.

    the last two are 3mm from the wall... you are not the only one who had difficulty interpreting this


    perhaps Jed needs to draw a diagram... for those new to velocity traverses.

    Typically traverses go across the diameter, from one side to the other.

    Starting from the center I think is what is throwing some people off.

    (It might be easy at the outlet, but it would take some extra finesse to do that through a hole in a pipe)

    If there is another dot close to the edge then I have no issue with the report averages, with the possible exception that a center dot might skew things a tiny bit higher.

    It is a bit hard to read some of the diagrams due to the resolution, BTW.


    My apologies for wasting time on this again.

    but the volume of air traveling at the speed you are stating is misrepresented is negligible compared to the volume of air properly represented!!! The effect on terms of the calorimetry is negligible!!!!

    Are you sure?

    The peak velocity is (normally) in the center, and the lowest flow is at the edge.

    The velocity directly affects the volume calculation, from which all output is derived.

    So what effect on power output is represented by a 10% overestimate of velocity? How does that scale with temperature?

    I see your point here, but you gotta admit, the ASHRAE diagram measuring points are pretty close to equidistant apart. Very similar to Mizuno's measuring points. Given the precision of his anemometer, I doubt the results would be significantly different. Also, as you noted, it is a little difficult to position the anemometer probe exactly to the nearest millimeter. I do not know how Mizuno does it. He is careful.


    A small diameter does not give much room to work in, however Mizuno's traverse locations are not at all similar to the ASHRAE recommendations (including 12 to 30 points along 2 or 3 traverses).


    The image below, when scaled to 65 mm, has the Mizuno points as red dots overlain on the ASHRAE diagram. This is similar to the point THH was making some while back.

    The flow near the tube wall is totally unrepresented, and as such the averaged velocity will likely be greater than the real average velocity for most flow types.

    In my case with the axial fan, the averaged velocity would greatly underestimate the actual average velocity.

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    *image removed because it was quite incorrect*

    That's an interesting paper. I love the Pitot static tube in Fig. 4! A first principle instrument, of the kind dear to my heart.


    The points chosen in the round duct in Fig. 7 are not equidistant apart (as you say), but they are close to equidistant. It seems the equal area technique is not much different from Mizuno's in actual practice. Also I doubt you will get the points to overlap and line up much better than Mizuno's Fig. 4. I don't see much room for improvement in that.


    Figure 11 shows a square duct with an array of sensors equidistant apart. That is a much larger duct than Mizuno's but anyway, it does not seem to be the Log-T or equal area technique.

    The rectangular duct sample positions seem a little weird but they may incorporate corrections for corners and whatnot. I didn’t really pay much attention to rectangular duct information when going through the various papers.


    Here are the duct velocity measurement standards.

    https://airmonitor.com/pdfs/co…ochures/BRO_Standards.pdf



    Here are some error estimates for various techniques and number of measurement points.


    https://www.epj-conferences.or…epjconf_icm2014_00010.pdf

    According to the dozen or so papers on HVAC testing procedures for determination of duct air flow I have read over the last couple of days, the anemometer traverse technique used by Mizuno can be improved, perhaps with a significant increase in calorimeter resolution.


    The recommended technique is known as the Log-T or equal area technique. This means that the anemometer test locations collected across the diameter of a cylinder are taken not at equal intervals (ie: 1 cm apart,) but at distances representative of equal volumes of air described by different radii. The results of the equal area anemometer readings will be weighted correctly when averaged. Results of equally spaced readings, when averaged, will be weighted increasingly towards the outside of the cylinder, because the area of the outer readings tested will be larger than the area of those closer to the center.


    How much the equal area technique improves the final velocity results compared to equally spaced readings depends on the actual velocity profile across the cylinder interior. Some reported tests suggest the error is typically between 5 and 10% of the true average velocity when the equal area technique is not used, and even 5% error was reported for two complete 90 degree traverses versus three full traverses at 60 degrees apart. It will be a while before I have a suitable test rig and enough results to evaluate this.


    See figure 7, page 14 for an example.


    https://www.tsi.com/getmedia/6…termine_air_flow?ext=.pdf

    Don’t forget that it is possible to replicate the mistakes of others and end up with the same results, wrong as they may be. The use of 7 to 14 um band IR thermometry on an oxyhydrogen torch flame comes to mind.

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    My personal opinion, based on minimal study, is that Para should get a much bigger fan.

    I have the proper fans coming. I pulled an axial fan out of a hair dryer just so I could do something while waiting for parts, and to try out the new anemometer. I can’t stand sitting around and waiting. Of course the axial fan turned out to behave quite differently than a centrifugal fan, and surprisingly did not reach laminar flow conditions at pipe D x 10 from the fan, which the literature suggests is plenty of distance for that to occur. In the meantime I will try out the heat equations to see if no excess heat occurs by blowing room temperature air through the pipe.

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    Ask the Swedes if somebody is willing to discredit him. I did (fact) and i find it hard to get anything negative back. Carl-Oscar gone? I dare you, dear Sir using your own logic. Prove it.

    Ask the “Swedes” about their opinion on anything about Rossi or any ecat they tested and silence is the answer. Nothing negative, nothing positive. Just nothing.

    Yes, I read the paper translation, but I am talking about how he calculated that based only in thermocouple readings and a custom made equation. That kind of energy input vs output estimation method will be shred to pieces as useless by anyone who does not think LENR is possible.

    Even those who believe LENR is possible should shun and “shred as useless” single point thermometry as a substitute for calorimetry. Temperature is not heat.


    Thermocouples are incredibly useful, and a fairly reliable instrument, but there a lot of ways something can have a higher temperature in one area than at another time. There are practical limits to what a thermocouple can reliably indicate about what it is measuring other than the temperature at one location.


    How well does a barbecue thermometer represent the temperature of the barbecue interior? If it reads higher one day at the same gas setting, is that evidence of LENR?

    This may be an axial fan thing.

    https://www.researchgate.net/p…2e626513dc000000/download

    Looks like it depends on how close to the fan the traverse is


    maybe there is a sweet spot where the velocity profile is flatter

    The flow should normally have settled by 60 cm, so it may be making a vortex in the tube.

    I think a diffuser is necessary to even out the flow velocity profile.


    Anyways, using the anemometer software calculation of the averaged traverses I got 5.24 m/s at the outlet and 4.98 m/s 15 cm from the outlet end, through a clean hole. The hole traverses also had the high flow at the pipe edges. These are my first two averaged traverses, so at least they are showing nearly the same value and that value itself seems possibly about right, even with the weird flow distribution.


    (These anemometers really could use a ruler built into the head since there is no way to look how far exactly the probe is in the hole in order to perform a proper traverse.)

    The anemometer traverses of the outlet of a 64 mm ID tube, 60 cm long, using a 65 mm OD axial fan were a little unusual (unexpected by me anyway).

    Several times higher velocity was measured at the tube edges than in the middle. This is the opposite of what I was expecting. This may be an axial fan thing.

    If I recall my own calculations correctly, the 4.4 x10-3 m2 area works out to 77 mm diameter, which combined with 4 m/s average velocity equals about 36 CFM, which is significantly more than the fan is rated to deliver.


    Anyways, aiming for a particular flow range is not a bad idea, and may be even motivated by a good reason. If there is a good reason, I am wondering what it is.