Two-Dimensional Viscoelastic Flow of Polymer Solution at Channel Junction and Branch

Abstract

Two-dimensional viscoelastic flows in T-shaped channels were observed by means of a flow visualization technique. We observed two kinds of T-shaped junction flows: symmetric and asymmetric junctions referred to as "type A" and "type B". Fluids used were water solutions of polyacrylamide and dextrose syrup respectively as viscoelastic and viscous liquids.In type A flow of viscoelastic fluid, two circulating secondary flows were observed at the upstream sides of entrance corners, but, with purely viscous fluid, they were not observed. With viscoelastic liquids flow direction changed more abruptly at the junction than with viscous fluids. In type B flows, circulating secondary flows were observed at higher flow rates than in type A flows.Lastly, flows were numerically simulated using the Maxwell constitutive model in perturbation method. Numerical results agreed qualitatively with experimental results in type A flows, but did not agree well in type B flows.

An experimental study of the merging flow of polymer solutions in a T-shaped microchannel

“…[27][28][29][30] Perera and Walters 31 predicted that fluid elasticity works against inertia and reduces the pressure drop caused by the abrupt change of geometry in a two-dimensional elastic flow through a T-shaped channel. Nishimura et al 32 observed secondary circulating flows at the upstream sides of the entrance corners in the flow of polyacrylamide (PAA) solution through a deep millimeterscale T-shaped channel, agreeing qualitatively with their Maxwell model-based two-dimensional flow simulation. In a recent study, Poole et al 33 predicted that fluid shear thinning can either promote or inhibit the bifurcation to asymmetric flow depending on the exact choice of Reynolds number.…”

Stagnation point flows in analytical chemistry and life sciences

“…132 Theoretical and experimental investigations on these types of ow can be found in ref. [133][134][135][136][137]. This review is focused on isolated stagnation point owsstagnations generated away from wallsexclusively.…”

Elasto-inertial instabilities in the merging flow of viscoelastic fluids

“…Perera and Walters 50 predicted a reduced pressure drop in the merging flow of an elastic fluid as compared to a Newtonian fluid. Nishimura et al 51 observed secondary circulations in the merging flow of polyacrylamide (PAA) solution at the upstream sides of the reentrant corners. Poole et al predicted that fluid shear thinning either promotes or inhibits the bifurcation to asymmetric merging flow 52 while fluid elasticity draws flow instabilities at a lower Reynolds number than in a Newtonian fluid.…”