Efficient Mixer to the Nanoscale

I believe that the correct answer is, "None of the above." Instead, see http://www.eurekalert.org/pub_releases/2009-10/dnl-mmc102709.php and watch the video. This is a magnetic particle stirring system, VERY new, but I believe exactly on target.

Hi,

ordinary ultrasound will create bubbles of some µm across that then will shrink and implode. This will change most materials so this may give a limit to usefulness.

Another limit will be if the liquid is too viscous and thus will not be agitated by the bubbles but only expanded locally and collapsing again: no mixing effect.

Cavitation nozzle: same situation as cavitation is the principle of ultrasound. But the effect is smoothed as the cavitation is spraying the droplets into air and thus no thermal or mechanical alteration of chemistry. Cavitation nozzle with or without additional compressed gas?

Cavitation nozzle may require much higher pressures then you may want to use.

High shear: how much shear velocity can you put on your liquid, there are severe limitations by the available bearings. Small clearances in the range below 10µm will need hydrostatic or aerostatic bearings.

RHABE