Numerical Study on Fluid-Structure Interaction in VFP Artificial Heart With Jelly-Fish Valve

We analyze sinusoidal pulsating flow that develops in the vibrating flow pump (VFP) artificial heart casing. In such system flow is induced by the axial movements of the vibrating pipe. Pipe is capped with the flexible thin disk that is called jelly-fish valve (JFV). Valve is opened during the downward pipe motion and is closed during the upward motion. Valve movement is very similar with the movement of falcon wings. It is due to the pipe motion and happens under the influence of fluid inertial, JFV spring, fluid shear and pressure forces. Authors utilized industrial strength CFD-ACE+/FEMSTRESS software package from CFDRC to analyze dynamic fluid-structure interaction, flow velocity field and time-dependent vorticity distribution. It was shown in the previous studies that blood hemolysis is closely correlated with the maximum values of vorticity fianction ω. In the paper we analyzed valve deformation, related flowfield and vorticity at different transient flow conditions. We can clearly conclude that dynamic formulation allows us to estimate and pinpoint with much greater accuracy the local maxima in vorticity. Vorticity peaks in two areas. First zone is at valve/pipe throat and second zone is at the casing throat. Vorticity is highest at the casing wall, thus pointing the direction for design improvements. Reduction in JFV stiffness helps to open valve wider and to reduce flow vorticity in its vicinity. These are work-in-progress results and additional studies will follow.