Quote:
Originally Posted by TinCup
When I talked to the folks at Brassworks they insisted that 3 cores weren't necessary. That their 2 core design was so much more efficent that the 3rd core wasn't necessary. I am running a 6 fin 2 row Brassworks now and it's not enough in these temps. Whether a 10 fin would be better I can not say. I either have to bite the bullet and purchase a 3 row or see if I can borrow one from one of our local club members to see it if better cools.
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Really …I said that?
I rarely make categorical statements about heat exchange theory so I am surprised to find myself quoted. Unfortunately heat exchange theory is a little more complicated than that and you would have to know far more variables to compare two cores e.g. tube shape and interior surface area, tube wall thickness, fin surface, fin thickness, fin depth etc. I would recommend
Fundamentals of Heat Exchange Design 2003 by Shah and Sekulic as a primer.
I will not review other radiators available but can compare some elements of Ford’s design to our core design.
Tube Shape & Design
Flattening a round tube into an ellipse forces more coolant to touch the wall than the center and that helps the heat (electrons) move from heat source(coolant) to heat sink (air). This is why Ford changed from inline round tubes in 28-29 to offset ovals in 1930-31. Today, we use highly elliptical tubes because they cool better due to their shape. If you use Ramanujan’s formula our flat tube has a 38% greater circumference of the perimeter of Ford’s 30-31 oval. Compare a 28-29 Ford round tube interior wall surface area to our flat tube and we have 2.93xs more. This improved contact of coolant-to-wall and wall-to-fin is where the heat exchange happens.
Tube Layout and Fin Surface
Our flat tubes have a staggered array to disrupt the air horizontally and fin surface disruptions occur between the tubes through embossing louvers in the copper. Ford began dimpling fins for the same reason in 1930 to reduce the impact from laminar air flow theory (the cushion of hot air that cool air rides on).
Volume & Flow
The aggregate coolant volume held by our 30-31 core is 5.12 oz greater than Ford’s design and 3.84 oz less in the 28-29. Tanks inlets and outlets capacity is the same.
Surface Area
Though we make 6 fin per inch 30-31 and round tube 28-29, most Model A radiators we sell are 10 fin per inch. It has 40% more surface area than Ford’s design and that is probably the greatest benefit to cooling.
Fin Depth
Henry Ford’s radiator is 1.875”thick and the tube size and center-to-center layout we use yields a 1.8125” thick core.
Our most common 10 fin per inch radiator design uses a more expensive tube, cost more in labor and uses more copper than Ford and other alternatives and yes our radiator cost $10-45 more than the other alternatives.
If forum readers have questions about our cores or radiators please visit our website. We add to it when people ask questions. You can also contact me directly.