Liquid film breakup mode at disk rim of centrifuge particle generator directly determines droplet shapes and sizes

which is a key factor to affect product qualities. A critical transition coefficient for spinning disk particle generator was proposed to characterize liquid film breakup transition characteristics from film to ligament

to extend to other breakup modes

and to establish critical equations for transition from direct droplet to ligament

ligament to fully ligament

and fully ligament to sheet. The experimental results of three working fluids and two disks indicated that disk surface wettability played key role for liquid film to become direct droplet or to transit from direct droplet to ligament

which incomplete wetting caused random critical volume flow rate with no direct correlation between disk diameter and critical volume flow rate. Critical volume flow rate increased with increasing disk diameter in fully-ligament and film modes. In general

the increase of liquid flow rate

rotation speed

liquid density

and viscosity drove towards film breakup mode. However

high surface tension force maintained liquid film in direct drop or ligament even at large flow rate and rotation speed. Moreover

increasing disk diameter enhanced both centrifugal force and surface tension and breakup mode did not change unless the force balance was lost.