Reactor tube conductivity is completely negligible

  • Recently, it was discussed whether the finite resistivity of the alumina reactor tube at elevated temperatures matters in any way for LENR reactions. It does not. You can completely forget about the currents through the reactor tube.


    Take a look in a good reference book like "CRC Handbook of chemistry and physics"


    If you keep in mind that excess heat was already observed at 800°C and if you look at specific resistivities at these temperatures you will find:


    Specific resistivity of Alumina is: rho_Al = 100000 Ohm * m
    Specific resistivity of Kanthal: rho_K = 1.03*1.45e-6 Ohm * m


    (The latter according to http://kanthal.com/en/products…istance-wire/kanthal-a-1/)


    For example: If you insert the geometric parameters of @me356 's last run, you will get


    R_Al = 100 MOhm
    R_K = 10 Ohm


    If you consider the current divider, and keep in mind that the total current was about 2 to 3 amps at 800°C


    there will be a current of I_K = 2.5 amp * 100 MOhm / ( 100 MOhm + 10 Ohm) = 2.49999975 A flowing through the Kanthal wire


    and consequently a current of I = 0.00000025 A flowing through the tube. Even if you assume that the resistivity of Ni LiAlH4 is negligible.


    Completely forget about the conductivity of the alumina tube.

  • What about the risk of troubling the thermocouple electronic ?
    2.5uA can trouble a high impedance amplifier, however for what I understand of thermocouple it is low impedance TEG.
    Maybe however is it more risky for ground loops ? few uA at 100V can kill some electronics.

  • What about the risk of troubling the thermocouple electronic ?
    2.5uA can trouble a high impedance amplifier, however for what I understand of thermocouple it is low impedance TEG.
    Maybe however is it more risky for ground loops ? few uA at 100V can kill some electronics.


    0.00000025 A = 0.25 uA :whistling:;)

  • 0.00000025 A = 0.25 uA :whistling:;)


    So that is only a 10% error on the TC current / temperature curve. Is that 150 degrees C, at say 1500 K (~1227 oC) Using absolute Kelvin as my top of the head guess here. That is quite a bit of error, "Majorana". And that is with all your assumptions rock solid. Let's not forget "reality" going down the dangerous path of dogma--- we've already seen what that has done to our field.


    But I do appreciate that other than the absolute style conclusion, your analysis mirrors my own some weeks back concerning hot ceramic conductivity. Yours looks and reads more clearly than mine-- thanks.

  • For example: If you insert the geometric parameters of me356 's last run, you will get


    R_Al = 100 MOhm
    R_K = 10 Ohm


    Can you post those calculations Majorana? For some reason I calculate approximately 45kOhm using these parameters:


    ∅D = 15mm, ∅d = 10mm tube, I have also ∅D = 16mm, ∅d = 12mm, but first one fits fine on the reactor tube.
    20AWG (0.812mm) Kanthal A1 wire, 3569.8mm length (R = 10Ω), 66-67 wraps with 50-100mm total leg length (<3% power loss)


    from an early post in me356's run.


    using the rho value of 100000 Ohm.m you quoted. Using pl/A, where l is (16mm - 12mm)/2 = 2mm = 2e-3m, A = 2piRL (where R is about (16mm + 12mm)./4 = 7e-3m) and L is 100mm which is the heater coil overlap.


    The result does sound a bit low though. Any pointers?

  • A few days ago I finished installing and testing a 2 kVA heater power isolation transformer. It seems to work well and eliminates the leakage current in the TC ground circuit. One surprise came in a second test which melted the type K TC in the core (1400+°C). A summary report has been added to the GS3 open archive:
    https://drive.google.com/open?…xJkjesxe4kNVh5WEt3cVEyOUk


    AlanG


    :)
    I volunteer my own experience running with a 0.5 mm diam Kanthal A1 coil, diam 8mm , length 85mm, where I managed to melt not only my NiCr based special alloy 1435C limit TC, mounted through the end of the pipe and in physical contact with the pipes inside, but the empty SS container as well, that was inside the Alumina reactor pipe. Max power in was 130V and 4.7 A at 100% duty cycle of the controlling SSR, translating into an effect of 611W. Now note, that we have here a runaway while a the coil is collapsing so likely the drawn current was more at failure (did not have data logging, as this was my first calib run and aimed at getting the temperature readings logged properly). It could not be significantly larger than 10A for more than a fraction of time, because the fusing is 10A.


    I would say that the electrical behavior if the alumina/mullite at temps at 1000C would be such that they actually are to be understood and reckoned with.

  • Why add another variable by introducing mullite? Stick with alumina that makes the thermal conductivity effect much simpler at the operating temperature of the reactor.


    GS4 will use a mullite tube because that is what Parkhomov uses and Rossi may use as well. In addition, there's evidence from Celani's work that Si may have a significant role in the reaction. As an alternative, an alumina tube could be used, with some silica added to the fuel.


    The mullite tubes we bought from Coorstek are very inexpensive compared to high-purity alumina, and won't need machining to use with Swagelok fittings.

  • Yes, let's keep the problem with reproducability ala Parkhomov, Rossi and Celani going. Add silica to the alumina reactor so that melting occurs at the reactors' operating temperature. Also don't purify the hydrogen so that the hydrogen sulfide from the piping will irreversably poison the nickel catalyst surface.

  • Yes, let's keep the problem with reproducability ala Parkhomov, Rossi and Celani going. Add silica to the alumina reactor so that melting occurs at the reactors' operating temperature. Also don't purify the hydrogen so that the hydrogen sulfide from the piping will irreversably poison the nickel catalyst surface.


    Ogfusionist's humor may slip by some. There is a funny guy down in there, who used to do stand up comedy at the "hungry i".

  • Longview, you can't be old enough to recall the "hungry i" restaurant. Anyway, this stellar fusion comedy would not have been appreciated.


    Seriously, while I'm still around it would be nice to see someone else attempt to initiate the hydrogen/helium fusion reaction using NiO.

  • "I agree, I wont forget the pursuit."


    I'm trying to keep this experiment from going off on tangents and it's not easy.


    Alumina has nothing to do with the reaction. Al2O3 FiberFrax is the support medium for the submicron NiO and undergoes no change if the fusion is controlled. The NiO catalyst must be reagent grade purity and never be exposed to sulfides. This requires a silver purifier immediately prior to the hydrogen in the reactor tube. The FiberFrax must be hydrogen (sulfide free) fired before impregnation with the NiO slurry. Can't over stress the need for control of sulfides as they permanently poison the NiO catalyst. The necessary -O- atomic surface layer is easily permanently replaced with -S- and deactivates the catalyst.

  • "I agree, I wont forget the pursuit."


    I'm trying to keep this experiment from going off on tangents and it's not easy.


    Alumina has nothing to do with the reaction. Al2O3 FiberFrax is the support medium for the submicron NiO and undergoes no change if the fusion is controlled.


    Possibly, but we don't really know that. The "NiO" is likely bound to the Al2O3 via oxygens.

  • Longview you're leaving me in the dust here. Too old to keep up. It all seemed much simpler years ago when I set up the FiberFrax/NiO train and recorded high thermal output at 830C with no apparent change in the green NiO catalyst. The RGA results seemed to indicate hydrogen fusion to produce helium. Seemed so simple, exactly what the sun was doing with the (-Ni-O-Ni-O-) periodicity along with the hydrogen interaction that overcame the Coulomb barrier. This array replaced the "gravitational" force.

  • Sorry, I was not trying to leave the subject. I was trying to keep the possibilities from being constrained by too many or too severe preconceptions. I may have been early in the chorus of those indicating that even hot alumina had little [electrical] conductivity. Now we see that on the surface of such ceramics there may be quite unexpected high temperature conductivity. Further, we have not even begun to consider some other aspects.

  • I used high temperature furnace lining material known as Al2O3 FiberFrax. Does not contain SiO2. The NiO resides on the surface and maintains nickelous valence as seen by its characteristic green color before and after the fusion experiment at 830 C.


  • Below linked is something more in line with what I recall was the high temperature version. I have seen a bit higher than the 1650 degrees C shown at this link, that is something in the 1700 degrees C range. Ogfusionist recently advised me of a test to distinguish the high temperature Fiberfrax. That is, if a particular type of torch could melt it, it was the lower temperature type. He indicated that a BernzOmatic would accomplish the same end. Years ago I found that I could fuse small amounts of copper or gold with such a simple propane torch. Essentially the idea at least is that the high temperature form of Fiberfrax should resist fusion by such a torch.


    http://www.matweb.com/search/d…053974d439f609b3010749709