An experimental and numerical investigation of particle dynamics in idealized aorta models grafted with a ventricular assist device outflow

Understanding the dynamics of particle-laden flows in the intricate geometry of aorta that is characterized by high Reynolds numbers and large Stokes numbers poses a significant challenge to both physical and numerical studies. Building upon our previous work, we aimed to verify and generalize our observations in four patient-specific aorta models to a broader range of anatomies. Based on a critical review of healthy human aortic morphology and dimensions, we developed two idealized computer-aided design (CAD) models. While the geometries are simplified, they together are expected to capture the major anatomic features of the general population. Each CAD model is grafted with a heart-assist pump outflow to study the transport of inertial particles injected at its inlet. A set of experimental and computational studies is conducted to investigate the Lagrangian trajectories of beads ranging from 0.4 to 1.2 mm at two physiological flow rates. The particle tracking velocimetry (PTV) measurements in thin-wall 3D-printed models are complemented with computational fluid dynamics (CFD) simulations using the same particle sizes, and inflow and outflow boundary conditions as in the experiments. The mapping of the particle fate and identifying the influencing factors provides an insight into an optimal graft candidate that can be used to improve the clinical outcome such as reducing the risk of ischemic stroke.