Abstract:The collision process of two deformed polymer drops undergoing a shear flow was simulated by using dissipative particle dynamics (DPD). The polymer drop is made up of many finite extensible non-linear elastic (FENE) bead spring chains. Both separating collision and coalescence collision were considered. The shear-induced anisotropic self-diffusion phenomenon of drops was studied. Besides capillary number (Ca) and viscosity ratio, the interfacial tension between two drops plays an important role in the coalescence collision or separation collision of the two drops. Due to the non-zero surface tension between two drops, a compound drop could be formed under certain conditions, and the compound drop tumbles in simple shear flow.