Simulação numérica de escoamento pulsátil na aorta torácica e aneurisma

• Ano de defesa: 2017
• Autor(a) principal: Matheus Silveira de Almeida Rodrigues
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Minas Gerais; UFMG
• Palavras-chave em Português: CFD; Tomografia; Aorta torácica; Endoprótese; Simulação numérica; Hemodinâmica; Aneurisma aórtico; Metodos de simulação; Bioengenharia; Engenharia mecânica; Aneurisma da aorta
• Link de acesso: http://hdl.handle.net/1843/BUOS-AU3H7B

Aortic aneurysm refers to an abnormal dilation of a segment of the aorta. The weakening of the vessel wall may cause its rupture, leading to massive internal bleeding. Surgical repair is preferably performed through the insertion of a stent. To optimize and develop new stents, it is essential to study the hemodynamic behavior of the aorta. Since in vivo experimentation is impractical, computational simulation is a viable option for the evaluation of the flow in new prostheses models. Hence, the aim of this study is to simulate the blood flow in a healthy thoracic aorta and in an aneurysm, in addition to proposing two types of stent for the repair of aortic arch aneurysms. Computational models were generated from CT scans but also constructed independently via CAD software. The boundary conditions were stablished as the velocity and pressure pulse of an adult, normotensive and resting subject; thus enabling the attainment of shear stress, velocity and pressure fields. Healthy aortic models were in conformity with each other (percentage differences of 4.66% and 3.22% for maximum velocity and pressure, respectively) and with Wiggers Diagram. The aneurysm greatly altered the flow: shear stress were 5 times greater than the physiological value. There was no significant difference between the Newtonian and non-Newtonian fluid model. At the end, the two different stents, one with straight endings and another with curved endings, were compared. The computational hemodynamic analysis showed that the model with curved endings obtained superior performance when evaluating the percentage difference of the maximum velocity in comparison to the physiological case. While the largest difference found was 2.6% for the curved endings model, the deviation of the straight end model reached 14.4%.