At 06:21 PM 7/17/2011, Joshua Cude wrote:
On Sun, Jul 17, 2011 at 1:26 PM, Abd ul-Rahman Lomax
<<mailto:[email protected]>[email protected]> wrote:
At 03:27 AM 7/17/2011, Damon Craig wrote:
Uhhh. I give up. How is a kink in a thermal curve evidence of
exothermic activity?
It's unclear what Damon is responding to. However, a change in the
slope of a heating curve will generally indicate some variation in
condition, such as changed input power or locally generated power.
It's a rough calorimetric technique, to determine what slope
corresponds to what immediate power.
I agree. The slope depends on the input power and the thermal mass
of the device. A doubling of the slope would correspond to twice the power.
Thanks.
If it were known that input power was constant, a sudden change in
slope could indicate additional power being applied. It is thus
"evidence." But it is certainly not proof, because that shift could
be a result of something else, such as a suddenly decreased coolant flow rate.
I don't think that's right. Since the water is flowing, it is not
part of the thermal mass, which consists of the ecat and the
infrastructure around it. So the rate of increase in temperature of
the thermal mass would not be significantly affected by the flow
rate. However, a sudden change in flow rate would produce a sudden
change in the temperature of the output water. So, I think what
you'd see is a vertical step in the temperature plot (during the
heating up phase), and then continued increase with the same (or
very similar) slope.
I think you are correct. Only if the flow rate change were gradual
could it create what appeared. Which seems pretty unlikely.
Remarkably, the Kullander and Essen data shows this phenomenon, with
apparent power doubling or tripling as the coolant temperature
passed sixty degrees. This apparent power is much lower than what
was asserted from overall heating on the assumption of full vaporization,
Agreed. Full vaporization must assume another very much larger
increase in the ecat power. Also, as you've pointed out before, the
linear (not saturating) behaviour of the temperature before 60C
suggests the power was higher than claimed, or the flow rate was
lower than claimed. Basically, the data is not consistent.
Well, I decided that it was possible that the linear behavior seen
could have levelled off at close to sixty degrees, maybe a little
above (and, remember, the input power was being slightly
underestimated, it could explain this.)
The Lewan demo temperature behavior is very hard to understand. What
would cause all that erratic behavior?
Many mysteries. Not very many answers.
