[nicozeg]

Well, this experiment finished with a partial success only.

I've been trying several impeller variations, and found a strange problem: When the pump fhas too much flow restriction, it enters a pulsating cycle where it quickly stops and start spinning. It don't happens in free flow condition, but when I try a max head test, it always happens when it reach about 35 cm.

To avoid it, I had to reduce the impeller dimensions, up to a piont where it can't generate more flow than the critical level. With the straight radial blades configuration, I ended with something similar to the impeller os that water-X shit. With the two disk option, I had to reduce the diameter to 28 mm.

At first I thought it was something with the motor electronics, where it automatically cut off the power when there's too much resistance, but the strange thing is that this happened at very different rpm levels depending on the impeller shape.

At the end, the performance at the best "stable" configuration was 300 L/H and 32 cm head.

This can still be useful to move water on a secondary loop in the system, but definitely not enough for cpu cooling.

An interesting side effect: With straight blades, this made an excellent air blower!

I don't know an easy way to measure airflow cfm, but for pressure I sunk the hose in water, and the level inside it was 30 mm lower than outside. As I remember, most fans can do only small fractions of an inch of static pressure.

Here are a couple pics of the two initial impellers I made. That was the starting point, and then I was progressively reducing the dimensions with the lathe.