Numerical Simulation Of Blood Flow In Locally Narrowed Blood Vessels

Atherosclerosis is the cause of most cardiovascular diseases.The study of hemorheology and blood flow behavior in narrow vessels is of great significance for the early diagnosis and treatment of atherosclerosis.In this paper,the steady flow and physiological pulsation flow of blood in narrow vessels are studied respectively.1)Analysis of steady blood flow in stenotic artery.A set of rheological data of human whole blood at 37°is utilized to construct the fractional Maxwell constitutive equation of blood.Consequently,the continuity and momentum equations of a fractional Maxwell fluid passing through a stenosis artery in a two-dimensional cylindrical coordinate system are established.With the help of the vorticity and stream function,the finite difference method combined with the L1 algorithms are applied to acquire the numerical solutions of the velocity,wall shear stress（WSS）and intravascular pressure gradient,and the validity of the algorithm is verified.Furthermore,the effects of the stenosis degree and stenosis shoulder length as well as various Reynolds numbers on the blood flow characteristics in stenosis are analyzed,which can provide a reference for formulating a clinical operation plan.2)Analysis of real pulsating physiological blood flow in stenotic artery.Two-dimensional governing equations of fractional order Maxwell fluid flow in local stenotic artery is established,taking entrance real physiological pulsating blood flow into consideration.Drawing support from finite difference method as well as L1 formula,vorticity and stream functions are bring in to acquire the numerical solutions of velocity,stream function,pressure.Meanwhile,the convergence of numerical algorithm and validity of model are validated by changing time and space step size and comparing to data from published literature,respectively.The distribution of blood flow in narrowed artery is discussed within a real physiological pulse cycle.Furthermore,the impact of stenosis heightδ,stenosis length parameter L₀,fractional order parameterαand relaxation timeλon crucial medical indicators embracing time average wall shear stress（TAWSS）,oscillatory shear index（OSI）,relative residence time（RRT）and pressure distribution are unveiled.Results turn out that the deceleration phase of real physiological pulsatile flow critically affects the progression of arterial stenosis,increasing fractional order parameterαweakens stenosis developing process,which influenced byλis contrary to α.