Eventos Anais de eventos
COBEM 2021
26th International Congress of Mechanical Engineering
IMPACT OF VISCOSITY ON BLOOD FLOW IN ASCENDING AORTIC ANEURYSM
Submission Author:
Gabriela de Castro Almeida , MG
Co-Authors:
Gabriela de Castro Almeida, Bruno Nieckele Azevedo, Julia de Almeida Silva, ivan fernney ibanez aguilar, BRUNO AZEVEDO, Angela Nieckele, Fabiula Azevedo, Gláucia Oliveira
Presenter: Gabriela de Castro Almeida
doi://10.26678/ABCM.COBEM2021.COB2021-2275
Abstract
Blood viscosity is established by several factors such as blood cell distribution, mechanical properties and/or percentage of red blood cells on the total volume of the blood. This last factor is known as hematocrit level. Higher the hematocrit rate, higher the blood viscosity. Understanding the consequences of the blood rheology in the flow field and how it can affect the vascular health is essential to help the diagnosis and treatment of patients that have different types of diseases. The identification of the impacts of different viscosities in the flow field in a realistic aorta geometry is important since measurement of the blood viscosity is a challenge, and its accurate value may not be available. Further, it can help to understand the correlation between blood factors and how it can affect possible pathologies in arteries. In the present work, the particular interest is related to patients with ascending aortic aneurysm, and how the flow structures can be correlated with the aneurysm growth or not. In this way, this research compares the flow in the major artery of the human body – the aorta – corresponding to two distinct years of two patients, one with aneurysm growth and the other without growth, considering the blood as a Newtonian fluid with two different viscosities (3.5cP and 7.2cP) and as a non-Newtonian fluid with 3.5cP limiting viscosity, using the Carreau model. The aorta dimensional model was generated by the segmentation of computed tomography angiograph images. Using Computer Fluid Dynamics, the flow is obtained with a commercial software, ANSYS Fluent. The most critical condition corresponding to the maximum flow rate during the systole period is considered. Due to the high flow rate, and large vessel diameter, the flow behaves as turbulent and it was solved with the RANS methodology employing the two-equation κ-ω SST turbulence model. It was observed a small impact of the blood rheology in the flow field. Similar wall shear stress distribution was also observed, although the viscosity presented a direct influence on its level.
Keywords
Blood viscosity, CFD, Hemodynamic, aorta
