Submitted to the Department of Materials Science and Engineering in Partial Fulfillment of the Requirements for the Degree of Master of Science in Materials Science and Engineering at the Massachusetts Institute of Technology February

The lattice-Boltzmann method was used for three-dimensional simulation of droplet breakup and coalescence in flow fields representative of those encountered in compounding of immiscible polymer blends. Quantitative confirmation of droplet deformation in simple shear was conducted using this method, and showed very good agreement with theoretical results. Droplet breakup in simple shear was simulated quantitatively, and agreed very well with both experimental and theoretical results. Capillary wave instability and end-pinching were simulated, and showed semi-quantitative agreement with theory and experiments. Breakup and coalescence of droplets in high-dispersed phase concentration was also simulated qualitatively. Limitations inherent to the model and future modifications needed for more accurate simulation of multiphase flow are discussed. Thesis Supervisor: Chris E. Scott Title: Assistant Professor of Polymer Engineering