Numerical fluid mechanics methods play a significant role in the design process of many devices, thus increasing comfort of life. One of the fields where their application is of the widest interest is medicine. The authors used the latest Computer Aided Design and Computational Fluid Dynamics software to analyze the flow in the pneumatic Ventricular Assist Device (VAD) with two different types of valves applied. In the study, a MEDTRONIC-HALL tilting disc mechanical artificial heart valve was compared with a three-leaflet polyurethane artificial heart valve designed at the Foundation of Cardiac Surgery Development, Zabrze. A comparison was made on the basis of the flow visualization inside the VAD chamber and the size of stagnation regions where the flowing blood may coagulate. The presented results were obtained for the steady state flow conditions and on the assumption that walls of the assist device, adapters and valves were rigid. The simulated fluid was blood. Dynamic viscosity of blood was defined according to the Non-Newtonian Power Law. Simulations were preformed for systole and diastole. The Ansys CFX v12 code was used to perform preprocessing, solving and postprocessing stages. Deformations of the threeleaflet polyurethane valve were obtained in SolidWorks 2009 and imported to Ansys ICEM v.12.
On the basis of the preformed analysis, it has been proven that the disc mechanical heart valve generates better flow conditions inside the heart chamber, especially when a risk of coagulation is concerned. Moreover, the flow observed inside the chamber when the disc valve was used is more homogenous and a single swirl occurring in the central part enables good washing of the connection of the diaphragm and chamber regions.
The analysis presented here is an integral part of the investigations conducted within the Polish Artificial Heart Programme.