Cooling fin spacing

[izax1]

Has anyone come over a mathematical expression for optimum cooling fin spacing for natural convection? WE need more cooling, and are playing around with fin design. Our finned wall of an electronic enclosure has a certain length which means we only have that much space for fins. If we increase the fin spacing (and I understand that can be advantageous) we may loose one fin. That may increase the air velocity, but it will also decrease cooling area. How can we calculate the crossing line?

Any clues will be much appreciated.

 

[MintJulep]

There are many factors to consider besides spacing. Search this forum for the free download heat transfer text book. Start reading from page 176.

 

[corus]

You need to look at the Reynold's number for this kind of thing, I think. For water flow in a pipe, for instance, the heat transfer coefficient varies with the water velocity to the power 0.8 so the product of velocity and area doesn't really change much if you increase one for a proportional decrease in the other.
You'd have to check the same principle for air flow. My guess it's the same.

corus

http://www.corusresearch.com

 

[izax1]

MintJulep

Sorry, but how do I find the free download heat transfer text book???

 

[MintJulep]

bernt,

See the post in the this forum titled "Free Heat Transfer Book"?

I'd give you the thread reference, but I see that it has been added to recently, and hence shows up on the first group.