Análise do escoamento sanguíneo na aorta abdominal e sua bifurcação ilíaca por meio de simulação computacional

Abstract

This study aimed to analyze the behavior of blood flow in the infrarenal abdominal aorta and its iliac bifurcation through computational simulation. For this purpose, a simplified geometric model of the aortoiliac region was developed, considering the abdominal aorta as the main vessel and the common iliac arteries as outlet branches. The geometry was built based on anatomical dimensions available in the literature, adopting a diameter of 18 mm for the abdominal aorta, 11 mm for the right iliac artery, and 10 mm for the left iliac artery. The simulation was performed using ANSYS Fluent, considering blood as an incompressible and Newtonian fluid, with a density of 1057 kg/m³ and a dynamic viscosity of 0.0004 kg/(m·s). A pulsatile velocity profile was applied at the inlet of the infrarenal aorta, representing a complete cardiac cycle of 1 second, and the time instants t = 0 s, t = 0.16 s, t = 0.26 s, t = 0.36 s, and t = 1 s were analyzed. The results were evaluated through velocity, pressure, and wall shear stress fields. The highest velocity value was obtained at t = 0.16 s, reaching 0.6444 m/s, corresponding to the systolic peak of the cardiac cycle. At the same instant, the maximum wall shear stress was also observed, equal to 16.06 Pa. In the subsequent instants, a reduction in velocity, flow reorganization, and the occurrence of reverse flow at t = 0.36 s were observed, which is consistent with the pulsatile nature of blood flow. The mass conservation verification showed errors close to zero, indicating numerical consistency of the simulation. The comparison with the study by Carvalho et al. (2021) demonstrated qualitative agreement regarding the velocity peak, deceleration phase, formation of recirculation regions, and occurrence of reverse flow. Therefore, the obtained results indicate that the geometry of the aortoiliac bifurcation directly influences the distribution of the analyzed hemodynamic variables.