Brownian Dynamics Simulation of FENE Dumbbell Model for Dilute Polymer Solutions in Shear Flow: Effects of Distributions of FENE Parameter and Relaxation Time.

Abstract

Brownian dynamics (BD) simulations of the steady and transient rheological behaviors of FENE dumbbell model for dilute polymer solutions in shear flow are reported. The simulations include examination of the effects of distributions of maximum allowable extension (FENE parameter b) and of relaxation time parameter α. Shear-thinning behavior of shear viscosity and the first normal stress coefficient, overshoot phenomenon in a start-up shear flow and stress relaxation for cessation of shear flow are also confirmed for distribution of b or α, which can be often observed in polymer solutions. Shear-thinning and overshoot behaviors are due to the non-linearity of FENE spring. Furthermore, it is found that the distribution of b has little influence on shear flow properties while the distribution of α can affect both the steady and transient shear flow properties under the distribution condition used in the simulations. In conclusion, BD simulation is a good tool to easily predict the effect of the distribution of maximum extension and relaxation time of dumbbells on the rheological behavior, however it can not calculate precisely the rheological properties in low shear rate region of λ0γ<0.1. This situation remains as a future task.