Abstract: In order to explore the law of internal flow and droplet formation in the process of injection,established a two-dimensional axisymmetric finite element model by Gambit,the numerical simulation method based on VOF model and moving-grid technology of Fluent was used to analyze the injection process of the shrink tube type piezoelectric printhead,and to establish the injection system to test the micro droplet injection to study on the formation mechanism of micro-droplet jetting,and to analyze the formation of droplet and attached droplet.The results show that vibration boundary movement caused internal pressure change,which led to the formation of the long liquid zone and micro droplets;the pressure value at the entrance of the inlet affected the production of droplet and attached droplet;available inlet pressure range existed in the specific vibration boundary movement.

Key words: micro-droplet, injector, piezoelectric printhead, simulation