The maths above is as simple as it gets in heat transfer. There are lots of stuff to worry about and to simplify:
* natural convection equations for the heatcore
* how to even calculate the effective surface area of a heatcore is hard to find
* the real scenario is actually cooling 2 heat points (GPU and CPU) - not cooling a uniformly heated fluid which is the usual case of a heat exchanger
* need to perform a heat balance with the GPU and the CPU - this is a conduction and convection problem all in one - i.e. pain in the backside
* simplify the problem by ignoring flow restrictions
* Plus several others I might have missed.
Maths is perfection - being a chemical engineer myself I know the difference between theory and practice. But with maths, it gives us quantitative numbers which we can work and compare with.
I've been in several extreme cooling boards and most folks are not even sure if their WC system is up to scratch. They just follow others and buy top of the line everything which in the end isn't cost effective as you could have bought the high end CPU and save yourself the hassle of researching and implementing watercooling.
The equations aren't hard for heat transfer, you just have to find and use the right one. By understanding the science, problems which may be trivial could be solved easily.
