基于计算流体力学的载瘤血管模型流体流动特性及数值仿真分析

Fluid Flow Characteristics and Numerical Simulation Analysis of Aneurysm-Bearing Vessel Models Based on Computational Fluid Dynamics

摘要: 颅内动脉瘤(IA)是脑动脉局部血管壁因结构异常或力学环境失衡，发生局限性异常扩张所形成的病理性病变，多数患者发病初期无明显症状，但破裂后易引发蛛网膜下腔出血等致命性并发症，致死率与致残率较高。深入探究IA的血流动力学机制，对破裂风险评估及干预策略制定具有重要意义。本研究采用计算流体力学(CFD)技术，基于载瘤血管几何模型，通过有限体积法(FVM)离散求解Navier-Stokes方程，在生理脉动血流条件下，对动脉瘤腔内的流体流动特性开展数值模拟研究，通过分析血流再循环、流速场分布规律、壁面压力及壁面切应力(WSS)等关键血流动力学参数，探究瘤腔内血流紊乱现象的诱发机制及其关键影响因素。数值仿真结果表明，动脉瘤瘤腔内存在显著血流回流区，流动分离效应与复杂涡流结构的形成进一步加剧局部血流不稳定性；低WSS区域与血流停滞区的空间分布与动脉瘤易破裂部位呈现高度相关性。

Abstract: Intracranial aneurysm (IA) is a pathological lesion characterized by localized abnormal dilation of the intracranial arterial wall, resulting from structural abnormalities or mechanical homeostasis imbalance. Most patients exhibit no obvious symptoms in the early stage; however, rupture of IA tends to induce life-threatening complications such as subarachnoid hemorrhage, leading to high mortality and morbidity rates. In-depth investigation into the hemodynamic mechanisms of IA holds significant implications for rupture risk assessment and the formulation of intervention strategies. This study employs computational fluid dynamics (CFD) technology and is based on the geometric model of tumor-bearing vessels. By discretizing and solving the Navier-Stokes equations using the finite volume method (FVM), numerical simulations of the hemodynamic characteristics within the aneurysm sac were conducted under physiological pulsatile flow conditions. Key hemodynamic parameters including blood flow recirculation, velocity field distribution patterns, wall pressure, and wall shear stress (WSS) were analyzed to explore the inducing mechanisms and critical influencing factors of flow disturbance in the aneurysm sac. The numerical simulation results demonstrate that there are significant blood flow recirculation zones within the aneurysm sac. The flow separation effect and the formation of complex vortex structures further exacerbate local flow instability. The spatial distribution of low WSS regions and blood flow stasis zones shows a high correlation with the prone-to-rupture sites of the aneurysm.