Post AulM8z9YewhBf8CDAW by mcdanlj@social.makerforums.info
(DIR) More posts by mcdanlj@social.makerforums.info
(DIR) Post #AulM8xP5AFvQEhRa5Y by azonenberg@ioc.exchange
2025-06-03T11:48:11Z
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What are the pros and cons of pinned vs finned heatsinks? I'm thinking specifically about rectangular pins like seen in my previous post (Wakefield-Vette 960 series).Initial thoughts:* Fins absolutely have to have airflow down their long axis. Square/round pins don't care, rectangular pins degrade but not horribly if you're oriented wrong* Pins weigh less* Fins have more surface area (at least, in the direction of airflow) in the same footprint* Fins have smooth unbroken channels while pins have interrupted channels. This probably Does Things to boundary layers and eddies and such but I'm not a fluid dynamics person.I'm sure somebody has spent years CFDing heatsink designs and can accurately comment on why both are in common use still. But not me.
(DIR) Post #AulM8z9YewhBf8CDAW by mcdanlj@social.makerforums.info
2025-06-03T16:38:01Z
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@azonenberg What I don't understand is why I don't see skived fins with vortex generators on the leading edge. Seems like it should be possible to mechanically process the leading edges of the fins to make integrated vortex generators to induce mixing from downstream turbulence between the vortices, to get cheap fins with high thermal conductivity. We've been using vortex generators for boundary layer management on airplanes for decades...It's such an obvious solution that there has to be a reason it isn't the norm for all skived fins, but I can't think of what the reason might be.
(DIR) Post #AulM908X0FT6iEiuCu by pro@mu.zaitcev.nu
2025-06-03T19:19:53.706318Z
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@mcdanlj @azonenbergLook at https://www.tchthermal.com/blogs/news/what-is-the-difference-between-pin-fin-and-plate-fin-heat-sinksAdding a machine step to blade heatsinks will decrease or eliminate their cost advantage BTW.
(DIR) Post #AulM92SoLosXviE85w by azonenberg@ioc.exchange
2025-06-03T11:54:34Z
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My gut feeling is that surface roughness is also super important for boundary layer behavior, but I can't put any numbers to it.