[Paper Review] Non-Newtonian Rheology in Blood Circulation

Taha Sochi|arXiv (Cornell University)|Jun 9, 2013

Rheology and Fluid Dynamics Studies19 citations

TL;DR

This paper provides a comprehensive overview of non-Newtonian rheological behavior in blood circulation, emphasizing shear thinning, viscoelasticity, yield stress, and thixotropy. It argues that while blood is often modeled as Newtonian for simplicity, non-Newtonian effects—particularly in microcirculation and porous tissue perfusion—are physiologically significant and should be integrated into hemodynamic modeling for accurate diagnosis and treatment.

ABSTRACT

Blood is a complex suspension that demonstrates several non-Newtonian rheological characteristics such as deformation-rate dependency, viscoelasticity and yield stress. In this paper we outline some issues related to the non-Newtonian effects in blood circulation system and present modeling approaches based mostly on the past work in this field.

Motivation & Objective

• To address the underappreciated role of non-Newtonian effects in blood flow, especially in microcirculation and porous tissue perfusion.
• To highlight the limitations of assuming Newtonian behavior in hemodynamic modeling despite blood's complex rheological nature.
• To identify key non-Newtonian characteristics—shear thinning, viscoelasticity, yield stress, thixotropy—driven by red blood cell aggregation and deformation.
• To advocate for systematic integration of non-Newtonian models into circulatory system simulations, particularly in stenosed vessels and microvascular networks.
• To emphasize the need for further research on fluid-structure interactions and non-Newtonian effects in diffusion and perfusion processes.

Proposed method

• Review of existing experimental, theoretical, and computational studies on blood rheology across various flow regimes and vessel types.
• Application of non-Newtonian constitutive models such as power law, Herschel-Bulkley, and viscoelastic models to simulate blood flow in rigid and distensible vessels.
• Use of pore-scale network modeling to simulate non-Newtonian flow through porous media, incorporating shear thinning, yield stress, and viscoelasticity.
• Adaptation of modified Darcy’s law for non-Newtonian fluids to model blood perfusion in biological porous tissues.
• Incorporation of fluid-structure interaction models to account for vessel wall elasticity and its influence on non-Newtonian hemodynamics.
• Analysis of hysteresis loops and time-dependent behavior to quantify thixotropic effects in repeated shearing cycles.

Experimental results

Research questions

• RQ1 How do non-Newtonian characteristics such as shear thinning and viscoelasticity influence blood flow in stenosed arteries?
• RQ2 To what extent do yield stress and thixotropy affect hemodynamic forces and wall shear stress in microcirculation?
• RQ3 How do non-Newtonian effects in blood perfusion through porous tissue compare to those in large vessels?
• RQ4 What is the role of red blood cell aggregation and deformation in generating non-Newtonian behavior at low shear rates?
• RQ5 How can non-Newtonian rheology be systematically incorporated into Darcy-based models of microvascular perfusion?

Key findings

• Blood exhibits significant non-Newtonian behavior, primarily due to red blood cell aggregation and deformation, especially at low shear rates.
• Shear thinning is the most prominent non-Newtonian effect, reducing viscosity under high shear and facilitating flow through stenotic vessels.
• Yield stress and viscoelasticity contribute to flow resistance regulation, with non-Newtonian effects acting as a protective mechanism in stenosed arteries.
• Thixotropic behavior is evidenced by hysteresis loops in cyclic shearing, indicating time-dependent structural recovery of red blood cell aggregates.
• Non-Newtonian effects are more pronounced in microcirculation and porous tissue perfusion than in large vessels due to lower deformation rates and complex geometry.
• Existing Darcy-based models for tissue perfusion neglect non-Newtonian effects, but modifications using power-law or Herschel-Bulkley models are necessary for accuracy.