Experimental and numerical flow analysis through arteries with stent using particle image velocimetry and computational fluid dynamics method

Abstract

In the paper, an experimental and numerical flow through various kind of arteries is considered. The flow analyses are carried out on the research set up using Particle Image Velocimetry Method (PIV). The individual components of the research set up are discussed and the measurement methodology is explained. The work consists of two parts. The first one is focused on modelling numerical simulation of the stent installation procedure using an expandable balloon and the flow domain design methodology is described. In the final part, an experimental flow test on an artificial silicone vessel (diameter 3.2 mm) with a stent is performed. The results of the experimental tests are compared with a corresponding numerical simulation. The paper presents numerical simulation for two different flow domains and the results obtained from the experimental tests. In both, the experimental tests and numerical simulation, the pulsatile time dependent flow and pressure characteristic are used. Hemodynamic parameters such as the time average wall shear stress (TAWSS) and velocity vector distribution are analysed. The flow was studied at four Reynolds number values (1223; 2257; 3198; 3762) for the straight vessel and at two values for the vessel containing a stent (1223, 2257). A diameter of the vessel was 3.2 mm. Pulsating blood flow based on the data from the experimental test was analysed. During the numerical simulation it was verified which regions of the vessel had TAWSS values below 0.4 Pa. A satisfactory correlation between outcomes of the numerical simulation and the experimental test was obtained. The flow analysis is conducted in ANSYS Fluent software. Additionally, the methodology for defining the velocity profile at the entrance is presented, in order to form the velocity profile in the first step of analysed cases. The study shows possibility to create a new research set up capable of testing various clinical cases of varying pressure values in the setup, or testing the effects of vessel geometrical changes, which allows observing an influence of those parameters on the fluid flow characteristic. As the analysis for the stent has shown, the regions of low TAWSS values are located in a close proximity to the stent struts.