How to make a two pass rad out of a one pass rad.

         Cut a notch in one header tank and insert and tig
         weld in a baffle. Then close up the hole and tig weld
         in the neck. The other end is just all capped off.
         --
         Paul Lamar ...No rotor no motor.

    Paul,

    Please doodle the water flow through a two pass radiator..


    Matt-

    OK Matt here it is.
    --
    Paul Lamar ...No rotor no motor.


How is that not only slightly better than having two smaller radiators
in series?  The second pass will be much less efficient than the first
pass section, right?  Didn't we just discuss not wanting to do this?


Matt-

On the face of it there is no difference. It is a compromise
to simplify  the plumbing at the slight expense of efficiency.
Perhaps the core volume may need to be 10% larger but in
terms of cost that is insignificant. There are fewer connections
(more reliable) and there is some heat conduction transfer from
the hot side to the cool side through the fins and the end tanks.
There is only one scoop and diffuser required instead of two.

The best way to do it is this. The top and bottom
sections must be thermally insulated from each other and supported
with plastic sides. It is called a counter cross flow heat exchanger.
Rather expensive to build and not available off the shelf.
Ed Klepies built one. He can build another upon request.
These are about 10% to 15% more efficient in terms of core
volume required.

http://www.rotaryeng.net/Counterflow-rad-core4.jpg
http://www.rotaryeng.net/cross-counter-flo-theory.gif
-
Paul Lamar ...No rotor no motor.

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