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Old 18th January, 2002, 11:17 AM
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Kaitain Kaitain is offline
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Surely you want turbulance within the fin area of the heatsink in order to effect better heat transfer? I thought that a laminar airflow over the fin area would reduce the heat transfer?
You want a turbulent air profile. Convective heat transfer is an order of magnitude greater in a turbulent profile than in a laminar profile.

The limit of the air flow that each models of heatsink have are limited. It will come to a pleatau of the curve and level off, any extra flow may not be useful but harmful as it may cause turbulance within the fin of the heatsink itself, thus lowering its efficiency.
First up, fin efficiency is a function of the heat transfer coefficient. The heat transfer coefficient (larger is better) is directly proportional to a power of the speed. This power is less than one but greater than zero, so yeah, it does reach a point where increasing the velocity of the air does not make a significant improvement but it does NOT reduce the rate of heat transfer. Unless you end up with dead airspace. And given the design of most heatsinks, that's unlikely.
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