Milli-PIV rheology of shear-thinning fluids

Abstract

Milli-Particle Image Velocimetry (Milli-PIV), which is an application of the standard PIV has been developed to measure the velocity distribution of complex fluids in a millimetric Hele-Shaw cell. A laser sheet is sent perpendicularly to the cell and the camera observes the PIV images via an internal optical prism. We studied, with Milli-PIV, a structural series of shear thinning xanthan fluids at different injection rates. We determined the velocity profiles in the thickness of the flow cell and discussed the accuracy of measurement. Using an inverse method, we calculated the constitutive parameters and showed that they are similar to those measured by rheology. The pressure gradient characteristic of the couple experimental conditions - fluid were also calculated from modeling the velocity profile.