OVERCOOLING

[Stephen M. Brown]

> water and the hot Cokes froze first every time !
> 
> So, I don't believe it (don't believe in electrons either), can't
> explain it, but I've seen it.  It's your turn ....
> 
> Tom Cloud

If you don't believe the hot water freezing faster thing, do a web search
for the PHYSICS FAQ's.  They have the physics explanation of the
phenomenon.  Something to do with the fact that you have a lot of movement
at the molecular level that improves heat xfer.  Don't believe me
tho...look up the FAQ.  

Also, with regard to the temperatures in the coolant, I'll whip out my
degree fer a sec:  suffice it to say that by increasing the flow of coolant
(pump faster), you'll might change temperatures, but you also affect the
heat transfer coefficient, which will also have an effect on the
temperatures.  They aren't pretty equations & MUST be solved
simultaneously.  In industry, we use the 10-zone heat transfer calculation
rule (split a heat exchanger up into 10 zones & solve each zone...cuts down
on the trouble you invoke) which is pretty much standard practice.  What am
I trying to say?  Well, unless you feel like setting this up on
Mathematica, I wouldn't even start any calculatin'...it can be a nightmare.
(Of course, if you make enough assumptions and simplifications, it could be
done...but yer accuracy would go to pot).   Just remember that Q = U*A*
LMTD.  
Q = heat load
U = overall heat transfer coefficient (easier to calc in the radiator than
the engine)
A = area available for heat xfer (also easier to calc in the radiator)
LMTD = Log mean temperature difference (awww, see it ain't fun)

BTW, my company makes software that does these types of simulations for
chemical processes (shell & tube exchangers, tho').  If anyone wants some
numbers, I'd be happy to oblige.   I'm kinda doubting anyone is really THAT
interested :)
steve

=====
http://www.off-road.com/4x4web/ford/bigbroncos
http://www.bronco.com