Inertial migration of rigid red blood cell particles in Poiseuille flow

Abstract

Inertial migration of single and multiple red blood cell (RBC) particles in a tube Poiseuille flow is studied using the lattice Boltzmann method coupled with the Galilean invariant momentum exchange method. Different blockage ratios, Reynolds numbers, and solid volume fractions are considered. In the single particle case, the RBC particle migrating in tumbling and rolling modes is called the tumbling particle and rolling particle, respectively. Simulation results show that the tumbling particle has a higher equilibrium position and longer rotation period than the rolling particle. For both the tumbling and rolling particles, when the blockage ratio increases, the equilibrium position moves closer to the tube centerline, and the rotation period becomes longer. The higher Reynolds number strongly affects the angular velocity of the RBC particle, leading the RBC particle to rotate faster; however, the equilibrium position is insensitive to the Reynolds number based on the limited observation. In the multiparticle case, the second and third inner particle annuluses unexpectedly form inside the Segré–Silberberg annulus as the solid volume fraction increases. Furthermore, smaller particles form the perfect Segré–Silberberg annulus at a lower solid volume fraction than larger particles. The third inner annulus of smaller particles is located further from the tube centerline than that of larger particles. This work is beneficial for understanding the motion of RBC particles in Poiseuille flow. It can positively contribute to the design of microfluidic devices for focusing, separating, and transporting red blood cells.