Atomization of high viscous non-Newtonian fluid into gas by spinning disk promotes intimate contact between the two phases. The size of droplets is directly determined by the ligament breakup characteristics

which is the key factor to affect the qualities of product. For spinning disk atomizer in this paper

the ligament breakup characteristics are analyzed

the ligament spacing model concerning with both the surface tension and viscous forces is proposed. Meanwhile

the ligament breakup mechanism is summarized. The results indicate that the viscosity always produces damping effect for the formation of ligament. With the increasing of viscosity

the ligament spacing will also increase. In general

the ligament number is influenced by the linear velocity of liquid film at the disk rim

while it becomes stable in fully-ligament mode. The disk with larger diameter and slower speed is advisable in the actual atomization process. For high viscous non-Newtonian fluid

the ligament number can be predicted by the Weber number

the equivalent Reynolds number and the flow index. This paper supplies the theoretical basis and further application for the design and optimization of centrifugal atomization of high viscous non-Newtonian fluid.