Simulation of a polymer drop in a shear field with dissipative particle dynamics method

Abstract

The dynamics of polymer drops in micro channel in steady-state and transient shear flow conditions are investigated using the Dissipative Particle Dynamics (DPD) method. The polymer drop is made up of 10% DPD solvent particles and 90% finite extensible non-linear elastic (FENE) bead spring chains. With FENE chains, shear thinning and normal stress difference effects are observed. For a polymer drop in steady-state shear field, the relationship between the deformation rate (D) and the Capillary number ( Ca ) could be divided into linear and nonlinear regimes. As the shear rate increases further, the drop begins to elongate; a sufficiently deformed drop will break up, and in the mean time, possible coalescence may occur for two neighboring drops. In a shear reversal, an elongated and oriented polymer drop retracts towards a roughly spherical shape. Due to the soft interaction of DPD particles, the tumbling phenomena of the polymer drop is not apparent even for large Ca.