Experimental and Numerical Study of Blood Flow in μ-vessels: Influence of the Fahraeus–Lindqvist Effect

Abstract

The study of hemodynamics is particularly important in medicine and biomedical engineering as it is crucial for the design of new implantable devices and for understanding the mechanism of various diseases related to blood flow. In this study, we experimentally identify the cell free layer (CFL) width, which is the result of the Fahraeus–Lindqvist effect, as well as the axial velocity distribution of blood flow in microvessels. The CFL extent was determined using microscopic photography, while the blood velocity was measured by micro-particle image velocimetry (μ-PIV). Based on the experimental results, we formulated a correlation for the prediction of the CFL width in small caliber (D < 300 μm) vessels as a function of a modified Reynolds number (Re∞) and the hematocrit (Hct). This correlation along with the lateral distribution of blood viscosity were used as input to a “two-regions” computational model. The reliability of the code was checked by comparing the experimentally obtained axial velocity profiles with those calculated by the computational fluid dynamics (CFD) simulations. We propose a methodology for calculating the friction loses during blood flow in μ-vessels, where the Fahraeus–Lindqvist effect plays a prominent role, and show that the pressure drop may be overestimated by 80% to 150% if the CFL is neglected.

Versatile Vessel-on-a-Chip Platform for Studying Key Features of Blood Vascular Tumors

“…We also found that RBCs accumulated in the central streamline of the channel producing a cell-free marginal layer next to the channel wall [28]. This other effect has been already described for RBCs flowing in microvessels smaller than 300 µm in width [23].…”

“…Indeed, around 25% of all deaths worldwide are related to acute problems in blood flow, such as thrombosis, embolism, or bleeding. Investigating the behavior of blood in confined environments may help to assess the mechanistic determinants of vascular-related diseases, to design new biomedical devices, to discover novel nanomedicines, or to develop more effective diagnostic tools [23].…”

Microfluidics Approach to the Mechanical Properties of Red Blood Cell Membrane and Their Effect on Blood Rheology

“…When blood measures are at the microscale, other effects may be observed, namely, the Fåhraeus [146] and the Fåhraeus-Lindqvist effects [147]. The latter, characterized by a dependence of the blood viscosity with the channel thickness, are perhaps the most important example [148]. In the range between roughly 300 µm and 10 µm of the tube diameter, the effective viscosity decreases up to 4-5 times.…”

Modeling and Simulation of Lipid Membranes

“…When blood measures are at the microscale, other effects may be observed, namely, the Fåhraeus [146] and the Fåhraeus-Lindqvist effects [147]. The latter, characterized by a dependence of the blood viscosity with the channel thickness, are perhaps the most important example [148]. In the range between roughly 300 μm and 10 μm of the tube diameter, the effective viscosity decreases up to 4-5 times.…”