A COMPARATIVE COMPUTATIONAL STUDY OF BLOOD-FLOW THROUGH PROSTHETIC HEART-VALVES USING THE FINITE-ELEMENT METHOD

The velocity, pressure and stress fields were obtained for the disk-type, tilting-disk and ball-type prosthetic heart valves in aortic position, for increasing Reynolds numbers up to 900, 1500 and 2000 respectively. Computer graphics of calculated velocities are presented, showing in detail the accelerated flow, recirculation and stagnation areas developed in the prosthesis. Maximum wall shear stresses were found at 0. 5, 1. 4, and 1. 2 diameters from the sewing ring downstream for the disk, tilting-disk and ball valves being the values of 55, 18 and 33 dyn cm** minus **2 respectively. In the vicinity of the occluder, maximum shear stresses of 38, 30 and 47 dyn cm** minus **2 respectively were computed. The flow characteristics and performance for each valve are compared, the results are presented in terms of energy loss and maximum shear stress. The velocity and stress field are compared with in vitro evaluations found in the literature.