Design of a cross-slot flow channel for extensional viscosity measurements

Abstract

In this work we present an algorithm for optimal shape design of viscoelastic fluid flow. A finite-volume viscoelastic code is coupled with the CONDOR optimizer [1] and an automated mesh generation and adaptation procedure, in order to find the shape of a given flow geometry, capable of achieving optimal performance. As an example of application we design an optimized cross-slot microfluidic chip appropriate for measuring the extensional viscosity of dilute polymeric solutions. The microfluidic cross-slot flow geometry is able to generate homogeneous elongational flow with regions of constant strain-rate, a requirement to produce meaningful rheological measurements.