Bahrami Saeed, Norouzi Mahmood
Faculty of Mechanical Engineering, Shahrood University of Technology, Shahrood, Semnan, Iran.
Clin Hemorheol Microcirc. 2020;76(1):9-26. doi: 10.3233/CH-200854.
Cardiovascular disease is now under the influence of several factors that encourage researchers to investigate the flow of these vessels. Oscillation influences the blood circulation in the volume of red blood cells (RBC) strongly. Therefore, in this study, its effects have been considered on hemodynamic parameters in the elastic wall and coronary bifurcation. In this study, a 3D geometry of non-Newtonian and pulsatile blood circulation is considered in the left coronary artery bifurcation. The Casson model with various hematocrits is analyzed in elastic and rigid walls. The wall shear stress (WSS) cannot show the stenosis artery alone, therefore, the oscillatory shear index (OSI) is represented as a hemodynamic parameter of WSS individually of time. The results are determined using two-way fluid-structure interaction (FSI) coupling method using an arbitrary Lagrangian-Eulerian method. The most prominent difference in velocity happened in the bifurcation and at hematocrit 30 with yield stress 6.59E-04 Pa. The backflow and vortex flow in the LCx branch grown with increasing shear rates. The likelihood of plaque generation at the ending of the LM branch is observed in hematocrits 10 and 20, while the WSS magnitude is normal in the hematocrit 60 with the greatest yield stress in the bifurcation. The shear stress among the rigid and elastic models is the highest at the ending of the LM branch. The wall shear stress magnitude among the models decreased at most of 24.49% by dividing the flow. Time-independent results for models showed that there is the highest value of OSI at the bifurcation, which then quickly dropped.
心血管疾病目前受到多种因素的影响,这促使研究人员对这些血管的血流进行研究。振荡对红细胞(RBC)体积中的血液循环有强烈影响。因此,在本研究中,已考虑其对弹性壁和冠状动脉分叉处血流动力学参数的影响。在本研究中,考虑了左冠状动脉分叉处非牛顿和脉动血液循环的三维几何形状。分析了具有不同血细胞比容的Casson模型在弹性壁和刚性壁中的情况。壁面剪应力(WSS)不能单独显示狭窄动脉,因此,振荡剪应力指数(OSI)被单独表示为WSS随时间变化的血流动力学参数。使用任意拉格朗日 - 欧拉方法的双向流固耦合(FSI)方法确定结果。速度最显著的差异发生在分叉处以及血细胞比容为30且屈服应力为6.59E - 04 Pa时。随着剪切速率的增加,LCx分支中的逆流和涡流增加。在血细胞比容为10和20时,观察到LM分支末端有斑块形成的可能性,而在血细胞比容为60且分叉处屈服应力最大时,WSS大小正常。刚性模型和弹性模型之间的剪应力在LM分支末端最高。通过分流,模型之间的壁面剪应力大小最多降低了24.49%。模型的与时间无关的结果表明,分叉处的OSI值最高,然后迅速下降。