I really don't think this is the "venturi" layout you're looking for. There is no significant reduction in cross section, just a hell of a lot of turbulent flow. I really think that even with a middle row of fans you'd struggle to remove that crazy amount of heat from there.
It is smooth not very turbulent through the fins it is basically less turbulent than the Avalon design given the proximate distance to the fins and as the fans are face mounted this will provide a much more stable and direct airflow across the fins even without baffles. Unless you have a simulator shows airflow I suspect you are speculating just as much as I am?
Testing this will not be an issue since the modular design of the boards means break down and re-configuring is simple. So I will be testing it with and without baffles to see what happens and get temp readings. Having a larger opening (volume) at the front and smaller space (volume) at the back along with having 2 banks of fans I don't think there will be any issues given this is based right off other server designs with a lot more obstruction of the airflow. I don't see this being an issue at all but again I will test it out and provide feed back. If it works I'll throw up the SketchUp plans so people can modify them for KICAD or what not be keen to see others work on this as well.
Not been stalking for a while. I'm not going to simulate this in CFD, because there are way too many variables to make the simulations tell us ANYTHING useful.
'Turbulence' essentially = Reynolds number, and is a function of length travelling over a surface. For heatsinks this large/long/arranged in a pattern, you're well into turbulent flow at any sensible air flow. You're going to need a hell of a lot of pressure to maintain the airflow you need to maintain the heat transfer you need, especially as the effective ambient will probably be 50C for the 2nd+ bank. Heat transfer is a function of temp difference, so each time you try and remove heat with the same air, it gets harder and harder.
The difference to commercial servers is:
1) Typically use centrifugal blowers, much higher air pressure [required to overcome frictional losses]
2) Are VERY VERY VERY VERY noisy, because the airflows required are insane.
Just look at a 1U heatsink fan on a typical Xeon. Even if the CPU is only 90W, you'll have a 45dba centrifugal heatsink for that ONE cpu, using a solid copper heatsink.
) . Where the first post can be summary of options, etc as the discussions continue. That way a new comer can simply read one place with links to individual threads if needed.
