Numerical modelling of fibre suspensions in newtonian and non-newtonian fluids

Abstract

Dissipative Particle Dynamics (DPD) models of fibre suspensions in Newtonian and non-Newtonian fluids are presented. The results are validated against available experimental data and numerical models. Firstly, the DPD method is studied and further developed to enhance its performance with regards to algorithms and implementation of no-slip boundary. A novel no-slip boundary is proposed and successfully applied to a variety of flows i.e. Poiseuille, Couette and complex flows. The algorithm is efficiently parallelized to speed up the computation. Secondly, the rheological properties and the orientation of fibres under Couette flows are investigated for the effects of different solvents, volume fractions, and shear rates. A modified version of the Folgar-Tuckera??s constant is proposed to deal with viscoelastic suspensions. Coupled with this, a prediction model for rheological properties is suggested and good agreement with simulated data lends some confidence to its use for both Newtonian and viscoelastic fibre suspensions. Lastly, the models are further extended to deal with several different applications.