Quote:
Originally posted by satanicoo
Ok, time to get deeper in this 'waterblock construction' thingy.
here are some questions, and i will ask more as i remenber them:
#1How you do you calculate the perfect fin area?
#2In cathar's ww i would just do 0.1 mm fins with 0.1 mm channels, but looks like that would be bad, why? what are the formulas/calculations/teories behind it?
#3How do you calculate the area of the sprayers?
#4i mean, in cathar's cascade block, he has 36 'tubes' with i dunno what diameter, making an X area of sprayers. How is that calculate, so that you calculate it without becaming low speed sprayers and without restricting too much the flow? #5The pump parameters enter here too right?
#6How do you calculate base ticness?
i saw somewhere it was related to the fins area?? :shrug:
#7why turbulance is better? water makes more contact with the 'walls'? #8Cant we add something to the water to make it 'contact' more with the copper?
#9how to calculate flow resistance in a block?
#10what is the impingement efect?
NOTE: english isn't my native language, normally i get quite confused, but in this treat if i do, i will just keep asking untill i understand it sorry 
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Well, until it shows up...
#1: You want to keep a channel-to-fin ratio between 1:1.5 and 1: 0.75. The actual width will be limited by the tooling you use. Btw, if you think you can make 0.1mm fins, think again, or let us know how!
#2: The calcs are based on Cathar's simulation.
#3: Trial and error.
#4: Again, the tooling is a big limitation. Even at a low speed, the design will perform well.
#5: As with many designs, the block will perform better with a higher flow rate. The trick is making a block that will allow you to use a reasonable pump, and reach a spot where the flow rate is at a point where increasing it further will yield little improvement.
#6: Bp thickness is related to the topside design, yes. If your design isn't efficient, then you have to use a thicker baseplate, to allow the heat to spread, so that it can be dissipated efficiently. otherwise, the coolant flow won't be able to pick up the heat efficiently, and you'll end up with a higher temperature difference, between the CPU and the inside of the block, which will result in a higher CPU temp.
#7: Water has certain thermal properties. Beyond that, it has properties as a fluid. By putting the water into turbulence, you're effectively reducing the resistance of the heat transfer to the water. Check out the OC article about it. Pins, fins, or whatever shape you see fit. Continous fins over the core area are extremely effective.
#8: At the detriment of its thermal properties, maybe.
#9: If you figure that one out, let us know! I've tried various formulaes, and applied them to each broken down individual components of a waterblock, but you also have to account for large variations in channel size differences (i.e. orifice plates), and that can be challenging to calculate, especially if a channel configuration doesn't fit a known model. It's often easier to just measure it, and an option to do that, if you are making the block from a CNC, is to make a plastic prototype, just for flow testing.
#10: First seen in a document about how to cool a Korean nuclear reactor, in case of emergency, it's the action of shooting water straight up against the surface to be cooled. The idea is that the collision throws the coolant into turbulence. It's cheaper to achieve turbulence this way, because you wouldn't believe what kind of flow rates (and pump) are required to put flowing water into turbulence!
I'll let you search for the documents I've mentionned. If you post a link to them, I'll answer more questions!