Accounting for residence-time in blood rheology models: do we really need non-Newtonian blood flow modelling in large arteries?
Accounting for residence-time in blood rheology models: do we really need non-Newtonian blood flow modelling in large arteries?
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DOI：
10.1098/rsif.2018.0486
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发表时间：
2018-09-01
影响因子：
3.9
通讯作者：
Arzani, Amirhossein
中科院分区：
文献类型：
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作者：
Arzani, Amirhossein
针对患者的计算流体动力学(CFD)是一种很有前途的工具，可以提供高分辨率的血流动力学信息。血液神学的选择是CFD模型中的一个假设，一直受到广泛的争论。众所周知，血液表现出剪切变稀的行为，非牛顿模型已被推荐用于动脉瘤的流动。目前的非牛顿模型忽略了在血液剪切变稀行为中起关键作用的循环形成。实验数据表明，在低切变率条件下，红细胞聚集和皱纹的形成需要显著的红细胞停留时间(RT)。本研究基于实验数据，提出了一种新的牛顿和非牛顿混合流变学模型，其中剪切稀化行为在高RT区被激活。考虑了基于图像的腹主动脉和脑动脉瘤模型，并使用最小耗散解算器进行了高分辨率的CFD模拟。拉格朗日粒子跟踪被用来定义反向粒子RT度量，并检测具有增加的轮流形成可能性的停滞区域。我们的新的基于RT的非牛顿模型显示了剪切稀化效应的显著减少，并提供了与牛顿模型定性相同和定量接近的血流动力学结果。我们的结果对特定患者的CFD建模有重要意义，并建议在大动脉血流中应重新考虑非牛顿模型。
Patient-specific computational fluid dynamics (CFD) is a promising tool that provides highly resolved haemodynamics information. The choice of blood theology is an assumption in CFD models that has been subject to extensive debate. Blood is known to exhibit shear-thinning behaviour, and non-Newtonian modelling has been recommended for aneurysmal flows. Current non-Newtonian models ignore rouleaux formation, which is the key player in blood's shear-thinning behaviour. Experimental data suggest that red blood cell aggregation and rouleaux formation require notable red blood cell residence-time (RT) in a low shear rate regime. This study proposes a novel hybrid Newtonian and non-Newtonian rheology model where the shear-thinning behaviour is activated in high RT regions based on experimental data. Image-based abdominal aortic and cerebral aneurysm models are considered and highly resolved CFD simulations are performed using a minimally dissipative solver. Lagrangian particle tracking is used to define a backward particle RT measure and detect stagnant regions with increased rouleaux formation likelihood. Our novel RT-based non-Newtonian model shows a significant reduction in shear-thinning effects and provides haemodynamic results qualitatively identical and quantitatively close to the Newtonian model. Our results have important implications in patient-specific CFD modelling and suggest that non-Newtonian models should be revisited in large artery flows.