Do you mean Paul_Vodrazka? I guess I don't understand your definition of "(direct) inpingement". I thought you meant "central inlet", like design#2.
I'm guessing that you're talking about the narrow channels, but not too narrow (like what Michael Westen posted in the OC forums.
I understand that the baseplate should be of the appropriate thickness, according to the design. In a maze type design, the baseplate is best left thick, since the cooling will occur over a significant portion of the baseplate (including the channel walls).
But then you say that with direct inpingement, it should/could be thinner. If you're talking about a center inlet, then I agree, hence design#2. I also tend towards design#2 (aka direct inpingement, aka center inlet) as performing better.
As for the calculation that you just presented, I understand them, however, the island being so close to the core would get hotter, would it not? This would increase the delta T, no? With direct inpingement (my favorite), it would work better, no?
I understand the limitation (as described by #rotor, i think) where if the baseplate is too thin, the coolant may not be flowing with sufficient speed to pick up the heat.
I also understand that *some* spreading is required, otherwise directly cooling the core would be very popular by now. I know that fins will do that (and really, that's what the baseplate is), but on an 80mm^2, with normal tools, unless you can put something together like Volenti did (i.e. the copper wire brush), there are not too many options. Even bandsaws are thick.
So I figure that there's got to be a balance between the heat dispersed by the baseplate/fin, and what the water can take away.
Maybe another approach... How much heat can a coolant (water) absorb, at reasonable speeds(i.e. flow rate, we can design a channel for a speed)? I mean what's the maximum rate, given a delta-T of say 10 degrees?
Knowing that, it might be possible to optimize the baseplate and fins.
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