PULSED FLOW OF RHEOLOGICAL COMPLEX FLUIDS IN CYLINDRICAL CHANNELS (EXAMPLE OF BLOOD CIRCULATION)
The paper presents the two-phase model to describe blood flow in large and in small blood vessels. Based on this model the study gives an explanation for long known features (effects) of blood flow in the vessels: dependence of the hematocrit (packed cell volume) on the diameter of the vessel, existence of cell-free plasma layer near the vessel wall, obtuse (as compared with the profile of Poiseuille flow) velocity profile of a blood; dependence of the blood viscosity on the diameter of the vessel. The researcher determines dependences of the blood rate and viscosity on the diameter of a blood vessel. With the flow of blood in small vessels (less than 200 μm), the rheological properties of the blood depend on the size of the vessel - the apparent viscosity of the blood drops with a decrease in the diameter of the blood vessel. To describe the flow of blood in small vessels, it is necessary to create an equation of state that depends (apart from other parameters) on the diameter of the vessel.