Droplet breakup in electrostatic spray based on multiple physical fields

• The droplet breakup model was proposed for simulating electrostatic spray in multiple physical fields. • Droplet breakup under electrostatic spray was studied by KH model. • The mesh target method was used to measure the droplet charge-mass ratio. • Better droplet distribution and charge-mass ratio can be obtained by adjusting process parameters. A droplet breakup model was proposed for simulating electrostatic spray in multiple physical fields. The static electricity, laminar flow and droplet atomization in COMSOL Multiphysics were coupled completely, and a two-dimensional simulation model was established. The process of droplet breakup and movement of electrostatic spray was revealed under the action of electric field, gravity field and air field. The electric field distribution under the needle ring electrode configuration was studied. The effects of different electrostatic voltage, needle ring distance and ring electrode diameter on droplet breakup characteristics, distribution uniformity and charge characteristics were analyzed. When the electrostatic voltage is -6 ∼ -7 kV, the needle ring distance is 4 mm, and the ring electrode diameter is 30 mm, the electrostatic spray effect is better, and the density standard deviation is as low as 0.04528 /mm 2 , 0.0559 /mm 2 and 0.06016 /mm 2 , respectively. Electrostatic spray has the characteristics of refining droplets, improving the uniformity of droplets distribution and controlling spray morphology, which provides a strong basis for the application of electrostatic spray in surface film preparation, dust removal, fuel injection and other practical engineering fields.