Flow of a blood analogue solution through microfabricated hyperbolic contractions

Abstract

In this work, the flow of a blood analogue solution past a microfabricated hyperbolic contraction followed by an abrupt expansion was studied. The shape of the contraction was selected in order to provide a nearly constant acceleration of the fluid at the centerline of the microgeometry. The flow patterns of the blood analogue solution and of a Newtonian reference fluid were captured using streak line imaging. The flow visualization results illustrate the complex behavior of the blood analogue solution flowing through the microgeometry, which is distinct of that observed for Newtonian fluid flow. For the blood analogue solution, elastic-driven effects are observed with vortical structures emerging upstream of the contraction, which are absent in Newtonian fluid flow. In this latter case the flow also develops inertia-driven instabilities downstream of the expansion. In addition, for the blood analogue solution at high flow rates the competing effects of inertia and elasticity lead to complex flow patterns and unstable flow develops