The integrated design of mechanical bi-leaflet prosthetic heart valves

Abstract

A flow model utilizing an irrotational, inviscid algorithm of vortex-ring elements simulating the leaflets and source/sink elements simulating the aortic root coupled with a boundary layer model has been developed to model the internal flow phenomena of bi-leaflet mechanical heart valves implanted in the aortic root. The inviscid representation evaluates the aerodynamic lift, the induced drag, the pitching moment and flow velocity along the leaflet surface thus providing data for evaluating the boundary-layer thickness, the shear stress and flow separation point by the boundary layer theory. Full integration with the geometry enables immediate updates of the flow solution when changes in geometry have been made. It is shown that the effects of the internal flow domain model are necessary in the correct evaluation of lift and drag for subsequent dynamic analysis. The environment presented provides for the ability to produce significant and immediate design changes so that crucial decisions may be made whilst still within the software design loop. New designs are shown along with data for the improved flow model.