Basic Research Of Red Blood Cell Rheological Properties In Capillary

The red blood cells (RBCs) play an essential role in all vertebrates and some invertebrates as the principal means of delivering oxygen to the body tissue. Biologically, a healthy human red blood cell (RBC) is a liquid capsule with a biconcave disk-like shape in the normal state, whose maximum diameter is generally quite close to the capillary diameter. When RBC goes through a capillary, it may experience significant deformation subjected to the stress of blood flow. The irregular motion and deformation of RBCs are probably relevant to several diseases in blood flow. Therefore, it is of great importance to investigate the motion and deformation of RBC in a capillary for revealing the mechanism responsible for the RBC mechanical behavior and providing valuable knowledge in the fight against the relevant diseases. on the other hand, we can obtain the conclusion that the deformation of RBC in capillary with different fluid environment by simulation data.On the one hand, this paper summarize a number of experimental, theoretical and numerical method on the mechanical behavior of RBC in microcirculation. On the basis of the specific characteristics of capillary microcirculation, all kinds of methods of advantages and disadvantages are analyzed. Then, a new numerical method combine Lattice Boltzmann Method with Level Set Method for simulating the flow of capillary microcirculation was proposed. Furthermore, discussing its principle in detail and verifying rationality of this numerical method.On the other hand, On the basis of simulation data, discussing the fundamental quantity to the influence of the red blood cells movement deformation, such as radius of RBC, viscosity and density. Furthermore, observing aggregation and dissociation of RBCs, and concluding RBC’s deformation in capillary microcirculation with difference environment.In the simulation of this paper, blood capillary was simulated as rigid-line round pipe and The RBC model was chosen as an elastic biconcave discoid thin membrane capsule containing Newton fluid, the flow in the round pipe was treated as one fluid with variable material properties, and such that the same governing Navier-Stokes equations are used for single flow, including momentum and continuity equations. Using Level-Set Method with Lagrange particles [PLS] tracking the boundary of red blood cell membrane and use Lattice-Boltzmann Method solving the fluid mechanics equation (Navier-Stokes Equation) to simulate the move and deformation of RBC in the Posieuille flow. And this single flow assumed as laminar flow which fulfill non-slipping boundary condition, this paper using Navier-Stokes Equation control the moving of flow. And descript this moving with Lattice Boltzmann Method in microscopic view, in addition, this paper using local Level Set Method to chase the interface, which due to discontinuous flow, combining Lattice Boltzmann Method with Level Set Method for simulating the flow of capillary microcirculation, providing research reference of deformation and motion of RBC in capillary microcirculation.