Kopernik Magdalena, Tokarczyk Paweł
AGH University of Science and Technology, Kraków, Poland.
Acta Bioeng Biomech. 2019;21(2):63-70.
The purpose of the work was to develop two-phase non-Newtonian blood models for medium-sized vessels with stenosis using power law and Herschel-Bulkley models.
The blood flow was simulated in 3D models of blood vessels with 60% stenosis. The Ansys Fluent software was applied to implement the two-phase non-Newtonian blood models. In the present paper, the mixture model was selected to model the two phases of blood: plasma and red blood cells.
Simulations were carried out for four blood models: a) single-phase non-Newtonian, b) two-phase non-Newtonian, c) two-phase Herschel-Bulkley with yield stress 0 mPa, and d) two-phase Herschel-Bulkley with yield stress 10 mPa for blood plasma, while flow took place in vessel with stenosis 60%. Presentation of results in this paper shows that stenosis can substantially affect blood flow in the artery, causing variations of velocity and wall shear stress. Thus, the results in the present paper are maximum values of blood velocity and wall shear stress, profiles and distributions of blood velocity and wall shear stress computed for single- and two-phase blood models for medium-sized vessels with stenosis.
For the two-phase blood models the influence of initial velocity on blood flow in the stenosis zone is not observed, the velocity profiles are symmetric and parabolic. Contrary, for the single phase non-Newtonian blood model, the velocity profile is flat in the stenosis zone and distribution of velocity is disturbed just behind the stenosis zone. The shapes of wall shear stress profiles for two-phase blood models are similar and symmetric in the center of stenosis. The biggest differences in maximum values of velocities and wall shear stress are observed between single phase non-Newtonian power law and Herschel-Bulkley blood models. The comparison of the obtained results with the literature indicates that the two-phase Herschel-Bulkley model is the most suitable for describing flow in medium-sized vessels with stenosis.
本研究旨在使用幂律模型和赫谢尔 - 布尔克利模型，为存在狭窄的中型血管开发两相非牛顿血液模型。
在狭窄率为60%的血管三维模型中模拟血液流动。运用Ansys Fluent软件实现两相非牛顿血液模型。在本文中，选择混合模型对血液的两相（血浆和红细胞）进行建模。
针对四种血液模型进行了模拟：a）单相非牛顿模型；b）两相非牛顿模型；c）血浆屈服应力为0 mPa的两相赫谢尔 - 布尔克利模型；d）血浆屈服应力为10 mPa的两相赫谢尔 - 布尔克利模型，血液在狭窄率为60%的血管中流动。本文的结果表明，狭窄会显著影响动脉中的血液流动，导致速度和壁面剪应力发生变化。因此，本文的结果是针对存在狭窄的中型血管的单相和两相血液模型计算得到的血液速度和壁面剪应力的最大值、速度剖面以及分布情况。
对于两相血液模型，未观察到初始速度对狭窄区域内血液流动的影响，速度剖面是对称且呈抛物线形的。相反，对于单相非牛顿血液模型，狭窄区域内的速度剖面是平坦的，且在狭窄区域后方速度分布受到干扰。两相血液模型的壁面剪应力剖面形状在狭窄中心处相似且对称。在单相非牛顿幂律模型和赫谢尔 - 布尔克利血液模型之间，观察到速度和壁面剪应力最大值的最大差异。将所得结果与文献进行比较表明，两相赫谢尔 - 布尔克利模型最适合描述存在狭窄的中型血管中的流动。
Zotero 插件