Abstract The lattice Boltzmann method is a numerical technique for solving the Boltzmann transport equation. Due to its simple use, this method is widely applied to simulations of porous, turbulent, multi-phase, complex boundary, etc. flows and has attracted considerable attention from researchers in recent years. One application of this method is in simulating blood flow inside blood vessels. Blood is made of blood cells and plasma. Although plasma behaves as a Newtonian fluid, blood exhibits non-Newtonian behavior due to the presence of blood cells, especially red blood cells. Atherosclerosis is one of the preva‎lent causes of death around the world. The buildup of fat or blood clots in arteries narrows them down. Hence, a study of occlusion in blood vessels is of critical importance. The present thesis examines blood flow as a non-Newtonian fluid inside occluded blood vessels. In this thesis, a brief introduction is provided about the Boltzmann transport equation and its relationship with the Navier-Stokes equations in addition to a number of non-Newtonian models presented for blood flow, and non-Newtonian blood flow is investigated in occluded vessels using the lattice Boltzmann method. Power-law, Casson, and Carreau-Yasuda non-Newtonian models were used to represent the behavior of blood in the simulation under study. In order to examine blood vessel occlusion, the occlusion geometry was modeled realistically, and suitable boundary conditions were applied. Then, the lattice Boltzmann algorithm was executed in MATLAB software. The results were then used to analyze the effect of occlusion on the changes in the velocity, shear stress, and pressure drop at the occlusion's location. The results indicate the velocity and shear stress increase at the location of the occlusion and that the changes in these parameters in this region cause vortices behind the occlusions.

بهمن اسدي

بهمن اسدي , ابوالحسن عسگر شمسي