Particle Image Velocimetry (PIV) analysis and Computational Fluid Dynamics (CFD) simulations have been performed on an innovative prototype of an implantable rotary axial pump. Numerically and experimentally estimated velocity and shear stress fields have been compared on several planes at different distances from the pump axis. An excellent agreement was generally observed in terms of mean flow velocity and viscous stresses, while the congruence of turbulent stresses was very good in some cases and less accurate in others. Further effort will be needed on both the numerical and the experimental side to better characterise near-wall flow features.

A fully automated numerical procedure has been implemented to enable 3D modelling of the physical behaviour of blood flow through an implanted Mechanical Heart Valve (MHV). For this purpose, a specifically developed Valve Cycle Program was coupled with a commercial Computational Fluid Dynamics (CFD) solver to implement a Fluid-Structure Interaction (FSI) model. A complete opening-closing cycle has been simulated by imposing physiological boundary conditions. A parallel laboratory circulatory mock-loop hosting a MHV has been manufactured to carry out experimental Particle Image Velocimetry (PIV) flow measurements. The predicted flow characteristics were found to be in good agreement with experimental observations. Both numerical and experimental results confirmed that flow patterns and associated shear stresses downstream of the valve result in a low thrombosis and haemolysis potential.

One of the main concerns when designing Left Ventricular Assist Devices (LVADs) is ensuring minimisation of thrombosis potential. In fact thrombus formation and resulting thromboembolism, which depend on the haemocompatibility of contact surfaces and fluid dynamics of the blood flow, are major risks associated to the use of LVADs as a long-term or permanent implantation. In the present study an existing LVAD prototype is numerically modeled with the aim to investigate the fluid motion field during the whole cardiac cycle of ejection and filling. 3D predictive numerical results are discussed against available experimental results.