Non-newtonian divergent fluid flow

Abstract

In this article the viscoelastic divergent fluid flow in the planar branched channel witha quadratic cavity is considered. Non-Newtonian fluid flow performed by the FENE-P (Finitely Extensible Non-linear Elastic-Peterlin) model that predicts the viscosity anomaly, limited finite longitudinal viscosity and elastic properties. The governing parameters of such fluid flows are the Weissenberg number ($\mathrm{We}$), Reynolds number ($\mathrm{Re}$), the ability of macromolecules to change its orientation in the flow and the disentanglement of polymer macromolecules $L^{2}$. The fluid flow symmetry loss effect at laminar regime is discussed. It is shown that under a certain set of values of $\mathrm{We}$ and $L^{2}$ numbers the fluid flow losses the stability and acquires an asymmetric shape.The aim of this work is to study the flow’s pattern at low inertial effects and model’s parameters. The solution was obtained on a non-uniform mesh using the finite volume method (FVM) in the OpenFoam software package. Special attention is paid to the influence of the properties of the fluid flow to the flow symmetry loss effect at small inertial effects. This effect is associated with the interaction of macromolecules of the dissolved polymer and the solvent flow (the main stream). Change the direction of flow leads to changes in conformation of macromolecules associated with their elongation and changes in orientation in the flow. This non-equilibrium configuration, in turn, leads to changes in normal stress. That, in turn, affect the flow pattern.