Some cooling notes :
Estimation for one heatsink and 2x CXA3070's operating @1950 mA
CXA thermal conductive surface : 27.35 x27.35 mm = ~748 mm^2
Applied at calculator :
Surface 2x 748= 1496 mm^2 ....Square root =~38.67 ..
So a hypothetical square chip with 38,67 mm sides was 'placed' ..
Heat to be dissipated : 100 Watts .
Flow rate of 2x fans combined @ 12 V : 200CFM ..
TIM thickness : 0.2 mm ( a sloppy job 200 micron layer )
~42°C Case temperature ....
A rough estimation ...
Not bad at all ...
I chose parallel operation for the 4x fans ....
Instead of 'series' ...
....
Maybe I should consider 2x2 ... A parallel combo of 2x " double in series " fans ...
Bulky ! ..It needs free 50 mm depth from inner side of top lid ...
The whole case is about 80 mm ... Not much space ...
Anyway ...
Remember that simply, parallel fans increase volume of air moving (flow rate ) keeping same pressure level,while series fans increase pressure ,keeping same flow rate level ..
Vertical air flow is guided ..
A tad of resistance is added ( the restrainer lid ) ,in order ,to "concentrate" the air intake ,more
into the middle(center ) fins and less at the side-fins of the heatsink ..
The CXA's will be placed at the center of the heatsink,length-wise.
The whole idea is to guidethe -massive- air flow towards being 'sucked in ' and 'run through' the center fins ,
until it 'exits' on the inner of the box ,to cool the rest of the electronics,before gets blown out from the 4x parallel fans ..
The compromise in the general air-flow is negligible ,compared to the higher ,'targeted' airf flow towards the center of the heatsinks ,allowing for more efficient ACTIVE cooling of that part .Instead of letting the heatsink 'suck ' in free flowstate ,with most of air escaping upwards to be blown out ,
the restrainer lid ,keeps the air flowing for a bit longer and futher 'down' the fin channels (mainly the center ones ) ,allowing for more fin surface to convect heat with cool air ,before it just gets blown out of the case ....
Thus more efficient cooling .
BTW ...
Did you know that free-fall parachutes have a 'restrainer' thing ,
to slow down the 'opening/engagement ' of the parachute ?
Oftenly ,things
have to last longer and /or go further ....
Not only vertical-wise ...
Forced air volume,passing through horizontal heatsink fins is such a case ,also...