Anyone have any idea how to calculate increased ampacity due to water cooling? For example, if the ampacity of aluminum is 700A per square inch, by how much could I increase the ampacity by submerging it in a river with a linear flowrate of water at an average (assume constant for simplicity) temperature of 45 degrees F?

Note: I'm aware electrical wire ampacities are based theoretically on the melting point of their insulation, not necessarily the conductors themselves. I'm not worried about wires though. In my example, say the aluminum has no insulation in a scenario where none is needed. I'm sure the answer to my original question involves some thermodynamics. I'm reviewing carnot cycles at the moment...

 

Wow, have I succeeded in stumping everyone? =P

 

You've succeeded in being to vague. This is a problem in thermodynamics, not electronics. The shape of the aluminum will have an effect on how fast heat can get out of it. The turbulence of the boundary layer, water velocity, angle of impingement, will have an effect. Tighten up your specs. I don't think anybody here is willing to write a book about a set of universal equasions for all conditions possible.

 

http://webcache.googleusercontent.c...pl.hp.com/techreports/Compaq-DEC/WRL-86-4.pdf

pg 14 is key to your questions