In this work, we use a phase-field-based multiphase lattice Boltzmann model to systematically investigate compound droplet dynamics in T-junction microchannels. Three main influencing factors are explored, including the interfacial tension ratio between the inner and outer interfaces, the capillary number, as well as the contact angle. We classify the droplet breakup patterns into six types based on the number of sub-droplets generated and the integrity of the core droplet and shell droplets. Numerical studies indicate that the above three factors significantly influence the pattern type of compound droplets. These findings provide valuable insights for the manipulation of complex droplets in microfluidics.

Compound droplets,T-junction,Lattice Boltzmann method,Breakup patterns