Stratified multiphase model for blood flow in a venular bifurcation

Area of Science:

• Biophysics
• Computational Fluid Dynamics
• Microcirculation

Background:

• Red blood cell aggregation and vessel geometry influence blood flow in venules.
• Previous studies show inconsistent relationships between red blood cell aggregation and vascular resistance.

Purpose of the Study:

• To computationally evaluate the effect of red blood cell aggregation on blood flow characteristics in a converging vessel bifurcation.
• To understand the relationship between red blood cell aggregation and vascular resistance in microcirculation.

Main Methods:

• A two-phase continuum mathematical model was developed, treating blood as a core of concentrated red blood cells and a plasma layer.
• Quemada's non-Newtonian rheological model was used for the core region, incorporating hematocrit and red blood cell aggregate size.
• Simulations analyzed immiscible fluid flow in a converging vessel bifurcation, predicting flow patterns in the collecting venule.

Main Results:

• Complex, three-dimensional blood flow patterns were predicted.
• Non-axisymmetric distributions of velocity, hematocrit, and shear stress were observed in the collecting venule.
• The model highlights the intricate interplay of aggregation and vessel geometry on microcirculatory flow.

Conclusions:

• Red blood cell aggregation plays a critical role in determining blood flow dynamics within microvessels.
• Computational modeling provides insights into the complex, non-uniform flow distributions resulting from aggregation.
• This work represents a foundational step towards realistic modeling of blood flow in the venous microcirculation.