Hemodynamics Analysis Of Aorta

Aorta is a section of the blood vessel with the morphologic characteristics of bend, tapering, bifurcation and so on. The periodic systole of left ventricle makes a nonlinear flow in aorta. Because of the influence affected by many factors, the blood flow in it is so complicated. There are a lot of evidences that many cardiovascular diseases are due to the dynamic factor to some extent. The abnormal blood flow may cause lesion of artery system, so it is important for having research on how artery system regulate the blood pressure and velocity. The hemodynamic research of aorta has many aspects, such as the regulatory mechanism of blood vessel and the stress distribution of the blood vessel. These researches have guiding significances in clinic.This dissertation has had research on the theory of the blood model mainly two-element model, impedance analysis, wave intensity analysis, the three-element model of the aortic hemodynamic and the merit and demerit of each model. Through the reasonable simplification and hypothesis, the finite element simulation model of blood has been established, so that we can have simulation of the blood flow in physiological conditions and in varying outlet boundary condition. All those we do above have provided mechanical basis of aortic blood flow for clinic and cure.The main work in this dissertation contains:1.Explain the hemodynamic model and have comparison of different aortic model.2.Simplify the model geometry and set different outlet boundary conditions, such as that the outlet pressure is zero, full developed fluid flow, outlet condition with extra pressure, the blocked outlet.3.Using ANSYS to establish and mesh the three-dimensional infinite element simulation model. Regard blood vessel as rigid wall and blood to be incompressible, viscous and newtonian.4.Simulating the flow situation in normal condition and in varying outlet boundary condition. Obtaining the stress and velocity distribution. Analyze the statistics of monitoring points by using wave intensity analysis. The feasibility of wave intensity analysis in finite simulation is then investigated.This dissertation indicates that different hemodynamic models have their own pros and cons. And the non-invasive wave intensity analysis can be used in clinic more widely in the future because of its time domain advantages. The three-dimension model is fit for the physiology situation but still should be researched deeply to validate the theory. In this dissertation, through the simulation, the stress and velocity distribution were obtained, then the dynamic factors which cause the cardiovascular diseases were researched. The comparision of the results in varying boundary conditions indicate how flow will change through changing the outlet boundary conditions.