MIZUNO REPLICATION AND MATERIALS ONLY

  • The smaller scoreboard fonts could go a size bigger yet, and maybe try bold font on the scoreboard digits, please.


    By 'smaller fonts' are you referring to the data cell labels? They can't be any bigger and still fit. The whole layout would have to be re-done.

    The 7-segment data numbers maybe could be made bold, I'll have a look next time the stream is paused.


    Other minor details are being fixed in-line, since the Python code can be edited while running. For example, can found an easy fix for the occasional black-out of the plotting window.

    Some stability issues have also been dealt with (hopefully), and if nothing else breaks tonight, I'll start MR2.6 tomorrow at 17:00 UTC.

  • MR2.6 was uneventful. The temperature matched calibration within 1°C at each power step and no radiation above background was seen. On a positive note the new streaming format worked very well and no crashes or dropouts were encountered.

    One observation worth noting, the cell pressure started to increase at ~275°C more than attributable to the standard gas law. The increase accelerated at higher power levels even after the temperature stabilized. This may result from a minute welding flaw that only opens above a certain temperature. Analysis of the cell gas now underway will give further insight into this.


    The data files have been added to the archive at https://tinyurl.com/y9kmpsz6


  • I have managed to shrink the calorimeter outlet muffler/diffuser to about 1/3 the physical size with little negative effect on the velocity flatness.
    The 10 cm gap seems important. Less open internal gap for the flow to jump seems to work poorly.

    a pic later.
    real easy to make

  • RGA post-analysis of the MR2.6 cell content showed contamination of typical atmospheric composition, N2, O2, H2O and OH-. Plenty of H2 and H3+ was also seen, but very little D2. This is surprising, because the only exposure to H2 was from the use of "LiAlD4" in MR2.3 on 17 April. The cell was thoroughly baked out several times since then, but evidently substantial H2 remained entrapped in the metals, and was only released at higher temperatures, while the Deuterium remained trapped as PdD.


    Regarding the cause of atmospheric leakage into the cell, I suspect the 316 alloy thermowell tube has been degraded by hydrogen embrittlement in extended exposure at high temperature. The cell will be disassembled for examination. I have parts for a new cell, using slightly thicker tubing for the thermowell. Once the welding is done it will be assembled and used for the next series, MR3.X. Two treated meshes will also be used for those tests.


  • Quick summary of recent Mizuno calorimeter replication and adjustments.

    I braced the new smaller air diffuser with a metal tile edge and spray painted it. Installed the pitot tube.

    Built a foam blower fan cover from 2 thicknesses of R10 pink foam board, carved it up neat, and then melted it with spray paint!! 😞, carved that off...and painted it with latex. Bent the pitot tube to clear. BME 280 air pressure, relative humidity and temperature sensor reinstalled and tested.

    Added thermocouple extension wires and relocated Reed temperature logger.

    Rerouted all wiring and cleaned up for easy disassembly of the box.

    Installed a 75 mm ID (3 inch) thin wall PVC pipe 15 cm long, as the sole inlet, three 2 mm holes drilled at 3, 6, and 9 cm from the outlet and installed at 10 cm flush with the outside (so 3.5 to 4 cm inside). That totally stabilizes the inlet temperature.

    Did a real nice calibration after fixing the noisy ADCs perfectly, finally. Re-calibrated the voltage dividers with the new clean data. The power supply is still noisy.
    The inlet temperature is affected by the calorimeter at the 9 cm hole closest the box. Moved to middle (6 cm) 2 mm TC hole. Spare TC installed in 3 cm from inlet hole.
    I can theoretically now properly measure inlet velocity and therefore volume easily. I wonder how the In-Out ratio will turn out?

    Did a perfect 12 hr run.

    Removed all the bubble foil and ran again for 10 hrs or so and that is just winding down now.
    The last 2 delta degrees seem to take for infinity to meet zero...

    It looks cool transparent but it definitely is lossy compared to bubble foil covered.

    .

  • The pink extruded foam that can be bought at Home Depot in the large sheets (at least I assume that is what it is) performed the worst in the fire test as shown in this video,


    (minute 9:56)


    If you do have a fire, the fumes will be terrible and toxic - so don't breathe any of that because you could pass out.


    The video linked above shows multiple plastic based insulators that don't burn as easily as the pink stuff - but all plastic based insulation will burn if given enough temperature and fresh air. The open exposed flame in the video results in a lower temperature and many of the fires burn out.


    But I don't have any good knowledge on which is the safest plastic based insulation to use. Maybe secure aluminum plates on top of it to act as a fire barrier?


    Or drywall - but that is messy, lots of dust. I think drywall might be the best option to block any fire from reaching the plastic.

  • I spent many years specifying and testing insulation products for acoustic applications. For situations where fire resistance is a factor, my preferred product is resin-hardened fiberglass board like this:

    https://www.owenscorning.com/i…ries-fiberglas-insulation


    It is Class 1 fire rated. The un-faced version has E84 index of just 5 for both flame spread and smoke index (lower is better). Typical sprayed urethane foam is rated at 20 for fire and over 400 for smoke.

    The maximum service temperature is 232°C and the R rating of 4.3 (1 inch thick) up to 13.0 (3 inch thick). The only drawback is the need to handle with gloves due to the exposed fiberglass strands.

    The foil-faced version is easier to handle but slightly less fire-resistant.

  • I am installing R6 foil lined polyiso board now. I cut the sides and back for the calorimeter last night.

    Just for fun, I am running a test with only those 3 sides installed, with a roughly 1 cm gap between the acrylic box and the foam boards. (When done, the foam box will be independent and removable from the acrylic box.)
    Notably, the delta T is already at the 9 hour, no insulation delta T peak already, in about an hour.


    I will cover the polyiso board layer with a layer of R10 pink foam board, and will eventually remove the high thermal mass acrylic box altogether.