Flow diverter stents simulation with CFD: porous media modelling

摘要

Intracranial aneurysm treatment with flow diverters stent (FDs) is a minimally invasive approach for use in human patients. Because this treatment is strongly related to blood flow, flow simulation by CFD is an attractive method to study FDs. Such flow simulations generally define geometries of aneurysms and stents in the computation by creating calculation meshes in the fluid space. For the other hand, generating a mesh in porous media (PM) sometimes represents a smaller computational load than generating realistic stent geometries with CFD, particularly for the small gaps between stent struts. For this reason, PMs become attractive to simulate FDs. To find the proper parameters, we investigated Darcy-Forchheimer model for porous media. The model describes the relation between the pressure drop and flow velocity considering a viscous permeability (linear model's term), and an inertial permeability (quadratic model's term). Finally, two stage studies were performed. First, we verified flow model validity at different angles in known flow conditions. Second, model validation was checked for a channel with no-slip boundary conditions. Results indicate that resistance calculated according to model has a difference of less than 3.5 % which is appropriate to characterize the FDs.