Abstract
Three-dimensional numerical simulation of a red blood cell (RBC) flowing through a micro orifice is carried out in this paper. The characteristics of the RBC deformation and the pressure loss of the flow are discussed as the flow rate is varied for several conditions. Nonlinear spring network model and immersed boundary method are employed to solve the motion of the RBC membrane and its interaction with the flow. A peak was observed for the deformation index and the pressure loss at the entrance the orifice. In this region, the RBC deforms due to the elongational flow and produces drag forces to the flow together with the blockage effect. The pressure loss decreases markedly as the RBC passes the orifice, and then shows a second peak as the RBC flows out from the orifice. These distributions are attributed to the stress produced on the membrane owing to the membrane deformation, and the obstruction effect of the RBC on the orifice. As flow rate increases, the value of the normalized pressure loss at the first peak increases due to the difference of the deformation degree of the RBC.
