Finlay asked a similar question. The answer is in the thermal model for the mounted area of the thermocouple.
The thermal model for Alan's thermocouple, mounted on the reactor tube, is different than Parkhomov's. Alan's thermocouple is in a center gap in the heater coil turns, the turns being wound directly onto the reactor tube. He has his heater coil portions on each side of center covered with a thick alumina tube, but the center area where the thermocouple is mounted is not covered (not insulated). Thus, there is thermal load to the environment (radiation, convection) from the area of the thermocouple that causes the thermocouple to read lower than the core temperature or even the surface temperature of the reactor tube right under the coils. Fortunately, Alan measured this differential in temperature between where he had the thermocouple on the reactor tube and the core temperature. On Fri, Apr 3, 2015 at 1:04 PM, David Roberson <[email protected]> wrote: > Bob, > > You appear to be making the assumption that excess power is being > generated within the core. Why would you expect the temperature inside the > core to be above the outside of the core unless some extra power is being > produced? Why 1200 C when the outside is at only 900 C? > > Something does not seem to add up in that calibration run, or perhaps I > just missed a fine point that you can help explain. Thanks. > > Dave > > -----Original Message----- > From: Bob Higgins <[email protected]> > To: vortex-l <[email protected]> > Sent: Fri, Apr 3, 2015 12:41 pm > Subject: Re: [Vo]:Re: CMNS: replication results coming later > > There were a couple of reasons. First, Alan was at near maximum power > when the reactor tube outside temperature was 900C and the internal core > temperature was over 1200C. The Kanthal A1 heater wire would have burned > out by the time the reactor tube temperature could have been driven to > 1200C, even if Alan could drive it that hard. Parkhomov had a different > differential between his tube OD and his core temperature than Alan did. > Alan measured his differential curve. If he had gone to 1200C at the > reactor tube OD, the heater wire would have been at or above its melting > temperature and the core may have been nearly 1400C. It was just not > practical. > > If Alan had the same insulating system as Parkhomov, his reactor tube > may have read nearly 1200C while his core was at 1200C. > > Another reason was the cool-down cycle time. Alan was uncomfortable > leaving the system to run un-monitored, so he had to shut it down in a > controlled cycle before he fell asleep. > > On Fri, Apr 3, 2015 at 10:16 AM, Daniel Rocha <[email protected]> > wrote: > >> Bob, why didn't you continue with until 1200 outside, I thought you >> were following Hank's advice. But, suddenly, the experiment stopped. Can >> you explain that? >> > >
