The sticky talks about "impingement" blocks as being "cream of the crop".
In grade five I learned that liquids are incompressible. So, if you're going to impinge with a liquid, maybe it's miniature plastic goldfish?
Impingement is the method used in water jet cutting, where the medium (usually water) carries a silica alloy (i.e. sand) to destroy a surface on the molecular level.
There are several types of processor water blocks that vary in efficiency:
1/ The squirt water on the hot spot, really, really, really lots! These are about as effective as rendering a garden hose upon your Aston Martin Vanquish after a hard drive through the mountains. I.e. something expensive will get broken. However, they are very inexpensive to produce.
2/ Turbulent flow, pin type heat exchangers are pretty effective and operate well at low flow rates.
3/ Linear flow finned types produce similar results to pinned types.
4/ Micro-channel heat exchangers are exceptionally effective as they can provide laminar flow (100% thermal boundary layer) close to the heat source. However, these require high pressure pumps. These types of heat exchangers are typical on Apple liquid cooled PCs.
5/ Multi-cellular heat exchangers flow exchange Reynolds numbers between low turbulence and laminar, as the passages. They do not require high pressure pumps and have a lower thermal resistance than micro-channel during high thermal density conditions.