Thermal Design: Heatsink for partly ducted 200LFM...

[Anders F]

I'm in need for a heat sink for a cPCI 6U board experiencing ~200LFM air
flow. We're talking an approximately 15cm wide and 9cm deep profile with a
height of ~9.7mm.

Having given up finding standard extrusions I'm thinking of having a custom
one made... Now, however, I'm in over my neck as I can't find any suitable
literature on the subject. My primary concern is fin spacing/thickness. My
guess is the spacing should not be much smaller than 2mm to avoid excessive
bypass. Base thicknes is another issue.

I'd like to get a (close to) optimal profile in the first shot....
Can anyone recommend literature or something? I know multiple software
packages are available - but I've also seen some prices on those!!! :-(

Cheers,
Anders

 

[Anders F]

I'm in need for a heat sink [...]
Can anyone recommend literature or something?

Or maybe a more suitable newsgroup?

Happy New Year =)
Anders

 

[Anders F]

I'm in need for a heat sink for a cPCI 6U board experiencing ~200LFM air
flow. We're talking an approximately 15cm wide and 9cm deep profile with a
height of ~9.7mm.

Having given up finding standard extrusions I'm thinking of having a custom
one made... Now, however, I'm in over my neck as I can't find any suitable
literature on the subject. My primary concern is fin spacing/thickness. My
guess is the spacing should not be much smaller than 2mm to avoid excessive
bypass. Base thicknes is another issue.

I'd like to get a (close to) optimal profile in the first shot....
Can anyone recommend literature or something?

If anyone (besides me) follows this thread they might find something usefull
on:
http://www.coolingzone.com/Content/Library/Papers/index.html#CoolingDevices
This free calculator would be fine if it could handle bypass:
http://www.frigprim.com/online/forcedconv_heatsink.html

Cheers,
Anders

 

[John Larkin]

I'm in need for a heat sink [...]
Can anyone recommend literature or something?

Or maybe a more suitable newsgroup?

Happy New Year =)
Anders

Your question is a little vague. Do you mean to slap a heatsink across
the entire back face of the board? What's the heat dissipation power
and distribution like?

And, given the jillions of standard heatsinks available, it's
surprising thay you'd have to extrude your own.

John

 

[John Woodgate]

I read in sci.electronics.design that John Larkin <[email protected]>

And, given the jillions of standard heatsinks available, it's surprising
thay you'd have to extrude your own.

Not jillions. We defined the jillion back in 1962, for the benefit of
the Sales Department, as '10^j' - a purely imaginary number.

 

[[email protected]]

I read in sci.electronics.design that John Larkin <[email protected]>
wrote (in <[email protected]>) about 'Thermal
Design: Heatsink for partly ducted 200LFM...', on Thu, 30 Dec 2004:


Not jillions. We defined the jillion back in 1962, for the benefit of
the Sales Department, as '10^j' - a purely imaginary number.
--
Regards, John Woodgate, OOO - Own Opinions Only.
The good news is that nothing is compulsory.
The bad news is that everything is prohibited.
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk

Thanks for the laugh. Happy New Year.
gg

 

[[email protected]]

I read in sci.electronics.design that John Larkin <[email protected]>
wrote (in <[email protected]>) about 'Thermal
Design: Heatsink for partly ducted 200LFM...', on Thu, 30 Dec 2004:


Not jillions. We defined the jillion back in 1962, for the benefit of
the Sales Department, as '10^j' - a purely imaginary number.
--
Regards, John Woodgate, OOO - Own Opinions Only.
The good news is that nothing is compulsory.
The bad news is that everything is prohibited.
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk