Finned water radiator tube ---

[Christopher Crowe]

Anyone know where to locate such a thing? I've been dealing with the very Capitolist Communist Chinese on this thing, to no avail. Have located axial finned tubing used in NASCAR, but nothing with radial fins (if I don't have this backwards).

Forgive my non-draftsman's drawing made for a potential overseas source... and all this is apprx.

Thanks,

Chris

[Jnovak]

Chris, if this is for a water radiator do not waste any time on this. The cooling capacity (heat transfer) is pretty much proportional to the surface area that is actually touching the water. That area in a 25mm tube is very minimal as only the water that is touching the inner surface is transfering much heat and the water in the center of the tube is not getting cooler. The best rads are those with lots of small flat tubes.

The above is an over simplification but is very meaningfull.

Jay Novak.

[nulrich]

The core of a Laminova heat exchanger isn't too different from your design:

http://www.opcon.se/web/Heat_exchang...leVersion=true

However, I'm with Jay, if you're trying to use your water tubes for additional heat rejection you're wasting your time. By far the most efficient way to cool oil and water is by heat exchangers explicitly designed for fluid to air heat transfer...otherwise known as radiators.

Of course, we could both be missing your intent, so feel free to explain.

Nathan

[thomschoon]

Here is an oil cooler version for 911's, you could alwys call them as they are very helpful.

[starkejt]

I was gonna say, reminds me of a 911 oil line.

[Tiago Santos]

Does the drawing say 8 fins per mm?

[RobLav]

Measure the surface area of the water tubes in an FB - they are not really that long especially since many cars run with one radiator and one big oil cooler - and compare that to the total surface area of all the tubes in a radiator. I don't believe you are gaining too much by playing in this area.

Besides, the surface contact area outside the tubes is in the engine compartment - a lot warmer than the air entering the rad. I think there's a thermodynamics equation somewhere here!

[Marty Nygard]

Overall heat transfer is a function of the relative heat transfer coefficients of the two fluids (water vs air), the the areas of the heat transfer surfaces and the LMTD (log mean temperature difference) of the two fluids. Some benefit would be possible with this configuration but only with relative cool air flowing across the fins (perpendicular to the tubes).
Marty
Former Boiler Engineer (Ret)