Numerical study of blood flow through stenotic and aneurysmatic artery of human organ

Abstract

Cardiovascular diseases such as heart attacks, strokes, atherosclerosis,stenosis and aneurysms have been considered asthe world’s highest cause of death. The frequently affectedarteries are the aorta, the coronary, the carotid, and the femoral arteries.It is a vital area of research for the flow behavior of blood, as well as the shear-thinning viscosity of blood. The study of blood flow has attracted the bioengineers, bio-medical researchers and numerical scientists over the past years due to its significant effect on several human cardiovascular diseases. In this thesis entitle “Numerical study of blood flow through stenotic andaneurysmatic artery of human organ”, three problems have been studied. The study on various kinds of stenosis and anuerysm enclousers and boundary conditions are summarized below:

Firstly, a computational analysis and simulation of blood flow through symmetricstenosis and asymmetric stenosiswith various flow rates have been studied. At inlet, the parabolic velocity profile is used and fixed pressure is used at outlet. Noslip conditions are used for velocity and homogeneous Neumann condition for the pressure at blood vessel. The governing mass, momentum and Oldroyd-B equation are expressed in a normalized primitive variables formulation.

Secondly, the blood flow simulation and numerical investigation have been considered through the permeable aneurysmatic artery for Newtonian, Oldroyd-B and their generalized fluids. The velocity profile and constant pressure are used at inlet and outlet respectively. The first aneurysm blood vessel is permeable and no-slip boundary conditions are used for rest of the vessel walls. A set of partial differential equations of conservation of mass, momentum and Oldroyd-B equations are expressed in a normalized primitive variable formulation.

Finally, a comparative study and numerical investigation have been carried out for blood flow through stenotic and aneurysmatic artery with incompressible Newtonian and non-Newtonian fluids including blood clot. The upper surface of blood clot is heated and stenosed vessel wall is cooleddown while noslip velocity conditions are applicable for all walls. The parabolic velocity profile is considered at inlet and pressure is remained unchanged at outlet.

The mathematical models are presented by various sets of partial differential equations for different physical problems with the corresponding boundary conditions. The dimensionless governing equations have transformed using appropriate nondimensional scale. The governing equations have solved using a finite element technique based on the Galerkin weighted method.

Results are presented in terms of velocity contourlines, pressure plots, and stream lines with vectors along vessel axis for simulation of blood flow. The graphical study have shown with the effects of the blood velocity, blood pressure along vessel axis, wall shear stress, drag coefficient, stress components,governing parameters namelyReynold numbers Re,Weissenbeg number Wi, Schmidt numberSc, and Pectlet number Pe for all models. Code validation is performed with previously published work and the results are found to be in excellent agreement. Reynold numbers Re, Weissenbeg number Wi, Pectlet number Pe

This results indicate that the blood flow and pressure strongly depends on the parameters such asReynold numbers Re, Weissenbeg number Wi, Schmidt numberSc, and Pectlet number Pe , the height of stenotic and aneurysmatic artery, permeable aneurysm artery, drag coefficient, and wall shear stress. The following outcomes in the research of numerical study of blood flow through stenotic andaneurysmatic artery of human organ may also be useful in bio-medical engineering.

(i) It hasshown that the effect of blood flow variables related to viscoelasticity is more significant at the throat of stenotic and aneurysmatic artery. (ii) The reversal flow have found at behind the stenosis and aneurysm region. (iii) The confined area or recirculation zones have originated at constriction of stenosis and middle of two aneurysm. (iv) It is found that the hemodynamical factors- blood velocity, pressure, turbulence, stress tensor and wall shear stress, play important roles in the localization of arteriosclerotic lesions affecting mass transfer phenomena at the arterial walls. (v) The transport of blood ingredients through permeable walls have played an important role to genesis and progression of arterial diseases. (vi) At abrupt contraction region having blood clot, the blood flow characteristics are affected for all modifications. (vii) The finding of the blood flow behavior on the wall shear stress is an important factor in the onset of arterial diseases which may be reported in medical science.