Influence of non-Newtonian properties of blood on the global transport of red blood cells

Abstract

(Received 30.05.1994; accepted 02.08.1994) The authors studied the global transport of red blood cells (RBC) in a cylindrical vessel. Human blood was considered as a homogeneous incompressible fluid. The level of transported RBC was approached with the use of different models of constitutive equation : i) a Newtonian model with apparent viscosity measured at a shear rate of 128 sec- 1 ; ii) a viscosity relationship for hardened RBC suspension ; iii) three non-Newtonian models (Casson equation, power law and Sisko type relationship). It was observed that the optimal hematocrit values obtained with the non-Newtonian models depended on flow conditions (vessel radius and pressure drop) and were generally greater in high shear flow than in low shear flow. It was also found that the optimal hematocrit was particularly low for rigid RBC suspensions. These theoretical results require experimental verification and more theoretical investigations of mechanical transport of RBC (oxygen transport efficiency) under different flow conditions.