CONTRIBUTIONS TO THE STUDY OF BLOOD FLOW IN THE ABDOMINAL AORTA AND ITS BRANCHES

摘要

Cardiovascular diseases are a major cause of death. Their development through the deposition of plaques onto the arteries and the subsequent formation of stenosis greatly affects the blood flow in the vascular system. Blood flow patterns depend on different factors, being the rheological characteristics of blood one of the most important.rnAlthough various publications have been dedicated to the study of blood flow in various geometries, they mostly assume the arteries as a rigid boundary. In the present work, the effect of the artery's wall deformation upon the flow patterns is investigated. Therefore, the prime goal of this study consists in the development of numerical models able to predict the blood flow in the region of abdominal aorta under deformable boundaries. The simulation was performed using adaptative dynamic meshes into the finite volume FLUENT software, in order to evaluate the influence of increasing the stenosis degree in the blood flow. The results show the influence of the deformable boundary upon the length and location of the recirculation zone downstream of the stenosis and also in the wall shear stress distribution and pressure drop across the obstruction. An experimental test facility was developed in order to validate the numerical results. A cam profile coupled with electro valves duplicates the periodic flow of the cardiac cycle observed in the iliac bifurcation. The results evidence thatrnthe severity of the stenosis affects the distribution of the velocity profiles across the obstructed vessel's section. It is also shown that the development of recirculation areas increases with the stenosis degree in post stenotic regions.