Caracterização experimental de escoamentos de simuladores de sangue em microdispositivos de plataformas analíticas com recurso à técnica micro-PIV

André Filipe Nobre Alves da

Key information

Authors:

André Filipe Nobre Alves da (André Filipe Nobre Alves da Silva)

Supervisors:

Viriato Sérgio De Almeida Semião (Viriato Sérgio De Almeida Semião)

Published in

11/24/2009

Abstract

The current work aims at the experimental characterization of the kinematic properties of both newtonian and non-newtonian blood analogs microfluidic flows. The micro-PIV experimental technique was used to obtain two-dimensional velocity information of microscopic flow fields. To study the effects of the rheological properties of the fluid on the flow behavior, the measured velocity data were compared against each other, against hydrodynamic analytical solutions, or when such solutions were not available, against other experimental data present in the literature, providing further insight into the influence of the rheological structure of the fluid on the flow. In order to obtain prepared solutions with rheological properties similar to those of blood, a parallel disk viscometer was used. The results provided by the micro-PIV study revealed that for newtonian microfluidic flows the velocity profiles were always in good agreement with those predicted by the macroscale hydrodynamic solutions. The velocity profiles obtained for the non-newtonian fluids, compared against the newtonian ones, were flattener in the central region, showing however a flattening decrease with increasing volumetric flow rate. The same study conducted over an expansion geometry revealed that the velocity profiles for newtonian fluids, were similar for low flow rate values. For the non-newtonian fluid it was observed a flattening in the centre of the velocity profile. However, when considering high volumetric flow rates, it was observed that the existence of inflection points on the velocity profile and the effect of the convective momentum transfer mechanism dominating over molecular diffusion.