[Amps] FW: RE: Liquid Cooling Systems

[G3rzp@aol.com]

Another point about the effects of local boiling can be found in the Nagayoka curves. The thin sheath of steam insulates the metal from the water, so it gets hotter, so the steam sheath gets a bit thicker, reducing the conductivity, so it gets hotter......it can actually run away thermally and melt the copper anode block. The Nagayoka curve plots thermal conductivity against temperature, and actually goes to a negative slope, explaining this phenomena.

This is more likely to be a problem with vapour phase cooling, but can happen in liquid cooled systems.

Interestingly, the problem didn't appear to be observed in the fireboxes of steam locomotive boilers, but this may have been because the watts/sq inch (or centimetre if you prefer!)were less, even though the temperatures were very high.

73

Peter G3RZP