School of Aeronautic Science and Engineering, Beihang University, Beijing 100191, China.
School of Energy and Power Engineering, Shandong University, Jinan 250061, China.
J Healthc Eng. 2018 Mar 14;2018:4312415. doi: 10.1155/2018/4312415. eCollection 2018.
Arterial stenosis plays an important role in the progressions of thrombosis and stroke. In the present study, a standard axisymmetric tube model of the stenotic artery is introduced and the degree of stenosis is evaluated by the area ratio of the blockage to the normal vessel. A normal case ( = 0) and four stenotic cases of = 0.25, 0.5, 0.625, and 0.75 with a constant Reynolds number of 300 are simulated by computational fluid dynamics (CFD), respectively, with the Newtonian and Carreau models for comparison. Results show that for both models, the poststenotic separation vortex length increases exponentially with the growth of stenosis degree. However, the vortex length of the Carreau model is shorter than that of the Newtonian model. The artery narrowing accelerates blood flow, which causes high blood pressure and wall shear stress (WSS). The pressure drop of the = 0.75 case is nearly 8 times that of the normal value, while the WSS peak at the stenosis region of = 0.75 case even reaches up to 15 times that of the normal value. The present conclusions are of generality and contribute to the understanding of the dynamic mechanisms of artery stenosis diseases.
动脉狭窄在血栓形成和中风的进展中起着重要作用。在本研究中,介绍了一种狭窄动脉的标准轴对称管模型,并通过阻塞与正常血管的面积比来评估狭窄程度。分别用牛顿模型和 Carreau 模型对正常情况( = 0)和狭窄程度为 = 0.25、0.5、0.625 和 0.75 的四个狭窄情况( = 300)进行了计算流体动力学(CFD)模拟,以进行比较。结果表明,对于这两种模型,后狭窄分离涡旋长度随狭窄程度的增加呈指数增长。然而,Carreau 模型的涡旋长度比牛顿模型短。动脉变窄会加速血液流动,导致高血压和壁面剪切应力(WSS)增加。 = 0.75 情况下的压降几乎是正常值的 8 倍,而在 = 0.75 情况下狭窄区域的 WSS 峰值甚至达到正常值的 15 倍。本结论具有普遍性,有助于理解动脉狭窄疾病的动力学机制。