Analysis of Hemodynamics and non-Newtonian Fluid Effects in The Corrugated Vessel Due to The Implantation of Intravascular Stent

• Main Authors: Wu. Bing-Shiun, 吳秉勳
• Other Authors: Ting. Ta-Wei
• Format: Others
• Language: zh-TW
• Published: 2005
• Online Access: http://ndltd.ncl.edu.tw/handle/21716407413625664501

碩士 === 國防大學中正理工學院 === 兵器系統工程研究所 === 93 === The vascular stenting has been accepted as a very effective treatment of occlusive vascular disease. But the implantation of the vascular stent will change the geometric shape of stenosed vessel to be corrugated and create some local hemodynamic features characterized by the flow separation, recirculation in the area close to the stent. Under the conditions of steady、transient and specific geometric shapes created by the implantation of different designs of stents, the numerical method has been used to solve the blood flow patterns near the stented vessel wall. Then the local ‘disturbed flow’ patterns were studied to know their close correlations with the localization of thrombosis and restenosis. In addition, the flows of the non-Newtonian fluid with hematocrit of 25%、45% and 65% are simulated to compare with the numerical results of the Newtonian fluid. This information provided insight into the importance and the effects of non-Newtonian properties on the blood flow in the stented vessel. Comparing with reference of the Newtonian case the consequences of the presence of a stent on the flow of blood inherent with the non-Newtonian properties can provide insight into how the non-Newtonian properties affect the flow patterns within the stent and the importance of the non-Newtonian properties. Velocity and its gradient of the flow field nearby the stent are decreased by the introduction of the non-Newtonian properties. At some specific time, the plug flow induced by the non-Newtonian properties will affect the hemodynamic features in the region close to the stent and increase the wall shear rate on the top of the apophysis comparing the numerical result of Newtonian fluid. It should be considered that the maximum value of wall shear stress created on the surface of the apophysis has to be limited to avoid the breaking of red cell membrane to result in the improvement of the design of intravascular stents.