Am 08.12.2011 20:13, schrieb Jed Rothwell:
Peter Heckert<[email protected]> wrote:
Thermal insulation can be used to avoid heat loss, but because the absolute
temperature was not much above ambient, not much loss is expected. Anyway,
thermal isolation is cheap and would eliminate the influence of ambient air.
1. Rossi's thermocouple was well insulated.
Yes, of course.
2. Ambient air has little influence even when you use only a Band Aid to
insulate the thermocouple. The water temperature dominates. Perhaps if you
had a fan blowing on the thing that would have a measurable effect.
Yes, as I wrote it is cheap and easy and therefore it should be done.
When it is cheap and easy to do then I am a perfectionist ;-)
It avoids mismeasurements when there are airbubbles at the measuring
position.
This is another problem with Rossis arrangement. The measuring point was
close to the highest point in the water flow and it can happen that air
bubbles accumulate at this point. This increases the thermal resistance
against the water and increases the effect of thermal crosstalk.
Peter
