In Silico Investigation of Rheological Characteristics of a Red Blood Cell Suspension in a Simple Shear Flow
Chih-Tang Liao1,2*, Yeng-Long Chen1
1Institute of Physics, Academia Sinica, Taipei, Taiwan
2Department of Engineering and System Science, National Tsing Hua Univeristy, Hisnchu, Taiwan
* Presenter:Chih-Tang Liao, email:ctliao@gate.sinica.edu.tw
Numerical experiments on the rheology of suspensions of aggregation-free and aggregate red blood cells (RBCs) in a simple shear flow are performed by the lattice Boltzmann method coupled with a coarse-grained membrane model composed of a spring network. We first match the RBC elasticity and aim to capture the whole blood viscosity dependence on the shear rate and RBC volume fraction. Adhesive forces among RBCs are taken into account to simulation rouleaux formation and to study consequences of RBC aggregation.

Our model successfully captures the shear-thinning behavior of the suspension as the shear rate increases, in qualitative agreement with experimental observations. We find that the suspension viscosity increases nonlinearly with the particle volume fraction. As the shear rate increases, the normal components of particle stress in the shear and vorticity directions increase, and the particle pressure decreases. These are attributed to flow-induced RBC alignment and weaker inter-particle interaction at larger shear rates. The relative viscosity, particle pressure, and normal stress differences are investigated for a range of hematocrits and shear rates.


Keywords: suspension, red blood cell, lattice Boltzmann method