Run 4 of our 2nd attempt to replicate the Mizuno-Ohmori Incandescent W Excess Heat Effect - 8JUN99
The most significant change for Run 4 was correcting the problem with the mechanical stirrer, which had failed during Run 3. We drilled out the PVDF bushing to provide enough clearance to handle the thermal expansion. The stirrer operated properly during Run 4, running at ~900 rpm throughout the run and drawing only 0.4 watts of electrical power.
A new W cathode and fresh 0.1M K2CO3 electrolyte were used for Run 4.
Also on Run 4, we applied the TFE shrink tubing to the W lead wire so that about 1 mm of the wire immediately adjacent to the W cathode was exposed. This was in an effort to reduce the black deposits on the W cathode that seemed to be coming from the burned TFE.
This photo shows the Run 4 cathode on the left and the Run 3 cathode on the right. As you can see, the Run 4 cathode is significantly cleaner.
Results:
The color legend and vertical scales for this plot are as follows:
Pin (0-200 watts)
Pout (0-200 watts)
Tcell (0-100° C)
Vcell (0-200V)
Icell (0-5A)
Tin (39-41° C)
The horizontal scale covers 4 hours.
The run starts with about 0.8 hours of equilibration time. During this time Pout closely approached zero (not visible since the approach was from a negative value) to within 0.5 watts. At 0.8 hours, we began stepping up the voltage in 5 volt increments (one step every 15 seconds) to acquire the I vs V data for this cell. On this run, we stopped at ~30 volts for ~0.2 hours to allow Tcell to climb above 80° C. Then we continued stepping up the voltage (Vcell) to about 145 volts and then left it there for the remainder of the run. Note the highly erratic Pin trace from hours 1.0 to 1.2. During this time, the cathode incandescence was unstable and at 1.2 hours, when Pin settles down at about 120 watts, the light from the cathode seemed to go out. Upon darkening the room, however, it was observed that the cathode appeared to be completely cold (i.e. no blackbody radiation) but covered with a dimly emitting sheath of spark discharges. Of particular interest is the disturbance observed in the Tin trace during this period (from 1.2 hours to 1.4 hours). Because of recent modifications to the calorimeter inlet-water regulation system, this disturbance is most likely a measurement artifact caused by severe electromagnetic interference! Conditions in the cell changed spontaneously and dramatically at about hour 1.4 where a sharp increase in Pin occurs. Without any warning or obvious cause, the cathode suddenly became quite hot, glowing bright orange, and the edges were covered with the tiny white flashes observed in previous runs. This condition persisted until the end of the run. Note that the disturbance in the Tin signal disappeared at this time.
From hour 1.5 to the end of the run, you can see the very disappointing bottom line for this run. Pout tracks right underneath Pin, about 1-2 watts below it on average. Since the cell was drawing about 1 ampere, we should expect Pout to be about 1.5 watts lower than Pin due to the caloric value of the escaping gases.
Note that the cell temperature (Tcell) rose up into the 90's on this run, reaching about 95° C at the end.
The peculiar appearance of the Pin trace at the end of the run is again due to the stepping down of the cell voltage. At first, Pin declines in an orderly manner but, when the gas sheath around the cathode collapses, the cell current more than doubles and Pin shoots up higher than it was during the run. Further decrease in voltage then brings Pin down to zero in a more-or-less orderly manner.
This plot shows the I vs V relationship for this cell during Run 4. Also plotted is the cell temperature for both the increasing V and decreasing V legs of this plot. The odd kink in the current density curve for increasing V is due to the wait at ~30 volts for the cell to warm up. A possibly significant difference between this plot and Mizuno's is the fact that our current density does not fall off suddenly when increasing the cell voltage. The gas sheath around our cathode develops slowly and steadily as we increase the voltage.
Comment, questions, and suggestions are welcome.