Numerical simulation of a 3D Bileaflet Mechanical Heart Valve using Fluid-Structure Interaction

Because of their long life span and durability, Bileaflet Mechanical Heart Valves (BMHV) are preferred for valve replacement. However, current BMHV designs induce calcification and thromboembolism, which is believed to be due to non-physiological flow and turbulence generated by the valve leaflets. Therefore, numerical flow simulations can provide relevant information for design optimization [1]. When simulating heart valves, the motion of the fluid, the movement of the leaflet walls and their interaction need to be taken into account. This can be done by fluid-structure interaction (FSI). A description of FSI methods for BMHV can be found in [1]. In previous work [2,3], an FSI algorithm with one degree of freedom was developed, supposing that the two leaflets perform the same motion. In this paper, an algorithm with two degrees of freedom is described, which allows asynchronous motion of the two leaflets. The algorithm is extended to perform a correct leaflet movement at closed and opened position and was tested with a 2D case in [4]. Subsequently, the convergence process is speeded up by using a variable time step size and extrapolation techniques. Finally, the algorithm is implemented for two 3D cases and the results are discussed below.