Numerical Simulation Of Hemodynamics In Arteries And The Formation Process Of Fat Embolism

It has been widely observed that atherosclerotic diseases occur at sites with complex hemodynamics,such as artery bifurcations and regions of high curvature.These regions usually have low or oscillatory wall shear stress,which is a main factor that results in thrombus formation.In addition,after the thrombosis,the stenosis will in turn have an effect on the hemodynamics.Hemodynamics is an important factor to determine the distribution of atherosclerosis and the development of vascular plaques.Therefore,it is of great significance to study the formation process of hemodynamics and embolism in the arteries.This study uses a virtual fluid that represents the fat particle.In the present work,a 2D carotid bifurcation was established,and the simulation was carried out by the computational fluid dynamics software.Due to the shear thinning of the non Newtonian model,the Newtonian model underestimated the blood viscosity,and then overestimated the size of the recirculation zone,which made the simulation result is not accurate enough;The vascular stenosis has an important influence on the movement of fat particle,as well as the formation of embolism;The fat particle may adhere to the vessel wall,due to the flow of blood,the fat particle spread slightly on the wall;The region behind the stenosis might be the next site of thrombosis;When embolism occurs,the velocity and WSS distribution become very complex,which is harmful to the vessel.Secondly,the hemodynamics of carotid artery aneurysm was studied.When the opening size?width or length of the carotid aneurysm increased,the shear stress of lower wall will be increased,and the pressure will be reduced.However,when the opening size is increased from 6mm to 8mm,or the width is increased from 8.8mm to 9.6mm or the length is increased from 5mm to 6mm,the change of WSS and pressure is not very significant.Overall,the increase in the size of the aneurysm will increase the shear stress of the lower wall,and reduce the pressure.At the end of this paper,we study the hemodynamics in aortic arch.The WSS of the inner wall is larger than that of the outer wall.When the inlet velocity increases,the wall shear stress increases correspondingly.When the aortic arch stenosis increased to 25%,50% and 75% respectively,the maximum velocity increased by 7.13%,77.26%,229.63%,respectively.When the number of aortic arch stenosis increased from 0 to 1,2 and 3,the maximum velocity increased by 22.49%,25.07%,25.32%,respectively.