Evaluation of the effect of viscosity on blood flow using viscosity models

Abstract

The study of blood hemodynamics and rheological properties, particularly blood viscosity, is essential for understanding and treating certain cardiovascular conditions. Blood is a non-Newtonian fluid, meaning its viscosity varies with shear rate, a behavior driven by the aggregation and deformation of red blood cells (RBCs). Accurate modeling of blood viscosity is therefore critical for simulating blood flow in both physiological and pathological states. In this work, various viscosity models were assessed to identify the most suitable that represents the blood’s behavior in relation to shear rate. Although the Newtonian model is simple, it fails to capture the non-Newtonian characteristics of blood, particularly at varying shear rates. In comparison, the Power Law, Walburn-Schneck, and Carreau-Yasuda models offer more detailed and complex approaches to modeling blood viscosity. The Effect of blood viscosity on the overall blood flow was evaluated based on the four viscosity models. The work was carried out in a MATLAB Simulation Environment. The Volumetric blood flow rate was evaluated from the Poiseuille’s equation using three viscosity models whose values were defined by shear rates ranging from (217.5 – 226.5)s⁻¹ . The percentage change in the blood volume resulting from changes in the viscosity was examined for each model. The two viscosity models (Power and Carreau models) concurrently reported equal percentage change of blood flux variation with the corresponding variation of the viscosity due to change in shear rate. This shows that any of the two models can be used to study the variation of blood flow to the viscosity with respect to cardiovascular complications.