CFD ANALYSIS OF A CUSTOM MADE MOCK CIRCULATORY LOOP

Valve prostheses are obtained through a design process involving in-vitro behavioural analysis with pulse duplicators that mimic the human heart and cardiac cycle. The pulse duplication device therefore plays an essential role during the in vitro analysis of a valve, which requires careful design. This last aspect is the focus of this thesis, in which supporting analyses were carried out for the creation of a new pulse duplicator model (currently under development at the Tissue Engineering Laboratory of the Rimed Foundation), which will be used to test a new mitral valve model in vitro. The customised pulse duplicator model aims to replicate left-sided chambers of the heart, consisting of atrial and ventricular chambers and offers the possibility to accommodate both the mitral valve (the main object of investigation) and the aortic valve. Computational fluid dynamics (CFD) was used to evaluate the current design, adopting finite volume-based solver. Specifically, three models were investigated: -??a simplified model with the atrium, ventricle and mitral valve; -??two models based on the original complete design of the pulse duplicator and representing its preliminary and final versions, respectively, which differ in dimensions; Once the CAD models were created, they were discretized by creating a mesh of quadrilateral elements, which reduced the error rate in the analysis phase. Simulations were then carried out with the aim of reproducing the cardiac cycle in its systole and diastole phases. The dynamic mesh method was used to take into account the movement of the mitral and aortic valves. From the results obtained, velocity fields in two regions located before and after the mitral valve were analyzed to assess the prototype's ability to reproduce an environment suitable for the in-vitro analysis of a mitral valve. Currently, the new pulse duplicator model can reproduce accurately the diastolic phase of cardiac cycle, while the obtainment of adequate behavior in the systolic phase is still object of research activity. To date, there is no work in the literature in which CFD has been used to support the design phase of a pulse duplicator. This therefore turns to be an innovative work aimed at increasing the efficiency and effectiveness of the design cycle.