Quote:
Originally posted by gone_fishin
by bigben2k
"The thinner the base plate, the more heat is available to be taken away, but if the flow rate isn't high enough, then the heat just sits there, and performance suffers" end quote
Technically I don't follow the first part. Increasing surface area makes more heat available to the coolant and the heat transfer rate (by velocity and properties of coolant) determines how much is stored up in the bp, higher velocity means higher transfer rate and lower block temp which results in lower die temp. Thinner bp means less stored heat energy to begin with.
The second part yes, higher flow rate brings higher coolant velocity.
I think what Cathar is trying to point out, is that he is using a restriction as a nozzle directly over strategic areas in his block. This lowers the overall flow of the loop but increases heat transfer because of the extreme velocity directed at various points of heat transfer, for a beneficial tradeoff. He is not using a restrictive barb nor do I.
I in fact do use a 5/8" OD barb as the inlet on my design.
The inner geometry of my block creates a velocity change throughout the short flow paths of the block and directly over the center of the core but also does not sacrifice as much overall flow volume. Both are radically different than what is available in the various mazes and open designs for an improvement,in my opinion
Edit: Observation, Did the other "ultimate" thread max out or something?:shrug:
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You caught me, I wasn't very accurate! I meant to sat that the heat is available at a higher transfer rate, which needs to be matched with a higher flow rate and/or flow speed. To be more specific, because the baseplate is thinner, the heat from the CPU will hit the bottom of the channel faster than it will spread out to the sides of the baseplate. If the heat is allowed to spread, then there is a lower deltaT between the block and the water, which reduces the performance.
So if the heat is available at a higher transfer rate, then there is an opportunity to achieve better cooling.
This is where flow speed, and fin design comes in: because a flat baseplate alone can be improved so easily with fins, it adds potential for better cooling. Add more flow, for more turbulence, and those make up, IMO, the three factors that are the most important.
Energy stored in the bp is irrelevant, once the rig achieves a balance point (my mistake).
A restriction, wether it's part of the barb or not, will achieve better cooling, because it creates a highly turbulent flow, which is great for improving the heat transfer to the water, as long as the accelerated coolant is located in a critical area.
The problem with this, again, is that it's awfully restrictive, and given the same pump, will reduce the flow rate. The reduced flow rate will deteriorate the performance.
As I remember, G_F, you and I went over this, some time back, but in your particular case, removing the nozzle gave you better performance. So again, the fin design is critical, because there may be some instances (Cathar for example) where an impingement may yield better results.
The "Ultimate waterblock? Theory" thread is very much alive, and is now (as of today) the most viewed thread in all the forums.
In fact, my design (#2) suggests a similar arrangement, but with fins in a radial pattern, because what's the point of having a center inlet if the fins are just going to go across it? I say, let's optimize the block for a radial, center inlet, set of fins that's less restrictive, impinge the thing, and watch in awe...
My design isn't tweaked out yet, but it's there.