Coupled fluid and solid motions in a leaflet type artificial heart valve: numerical and experimental verifications

A computational model with coupled fluid and solid motions is presented for mechanical heart valves (MHVs) design and to provide a better understanding of valve performance under various operational conditions. The computational fluid dynamics (CFD) simulations were performed on a leaflet type mechanical heart valve (MHV) using experimental measurements as the input parameters. In the current study, a three dimensional unstructured moving grid finite volume method is applied to simulate the coupled leaflet movement and fluid flow field. A multi-block grid generation and moving boundary techniques were implemented in a numerically simulated cardiac cycle. This way, the grid only needed to be generated once and no grid stretching was necessary, thus ensuring accuracy and efficiency of the solution. The motion of the solid structure could be obtained from the solution. The flow experiment was conducted using a Medtronic Hall tilting disk MHV to demonstrate the phasic occluder motions and the corresponding fluid velocity and pressure fields. The experiments were conducted in a pulse flow loop that closely simulates physiologic conditions. The flow rate and the pressure fields obtained were used as the input for the numerical simulations. A high speed video system was employed to visualize the leaflet motion and the experimental results were used to further refine the numerical simulations.