Rheology of red blood cell flow in large geometries

Authors: van Wyk, S.v.W., Prahl Wittberg, L., Do-Quang, M., Fuchs, L.F.
Document Type: Conference
Pubstate: Published
Journal: 8th International Conference on Multiphase Flow (ICMF), Jeju, Korea (2013)
Year: 2013


When studying disease development in arteries, it is important to understand the local variations in blood rheology. Blood flow in large arteries is often assumed to behave as a homogeneous fluid, an assumption that is not entirely correct. The local viscosity changes with the local concentration of Red Blood Cells (RBCs) and the rate of shear strongly influences the Wall Shear Stress (WSS) and its gradients, physiological parameters important in the study of atherosclerosis. Moreover, the flow behavior of RBCs is influenced by the geometric structure of the flow environment. In experiment, rheological properties across a tube cross-section are difficult to measure if non-invasive techniques are to be used. Therefore, rheometric devices are constructed of simple geometries to measure the bulk rheology. In this study, the Lattice Boltzmann Method is used to model the blood as a particle suspension of RBCs. The RBC Volume Fractions (VF) investigated corresponds to 1, 2 and 5%, and both a channel and a tube flow are considered. The results display large differences in RBC distributions and velocity profiles. Estimated from existing viscosity models, the viscosity distributions are found to display variations of up to 5% when comparing the two geometries. This is of importance since errors in quantifying the viscosity can lead to miscalculations of the physiological variables.