Abstracts: ASAIO Bioengineering/tissue Engineering Abstracts
HYDRAULIC PERFORMANCE CHARACTERIZATION OF AN AXIAL FLOW PEDIATRIC VAD PROTOTYPE
Computational fluid dynamics (CFD) was extensively used to predict the hydraulic performance for an axial flow, magnetically levitated, pediatric VAD. Validation of these CFD predictions is critical prior to proceeding with a final magnetic suspension / motor design for the VAD. For design validation, a pump prototype must be built for performance testing.
A modular test rig with a mechanical suspension was employed for preliminary flow measurements of a prototype. Each internal fluid region of the pump was manufactured by stereolithography (SLA) directly from solid modeling drawings of the CFD model and a preliminary magnetic suspension design. The pressure-flow and axial / radial fluid force measurements were determined for a range of operating conditions. The axial fluid forces exerted on the rotor were measured via a load cell. Pressures were measured at locations along the axial length of pump to capture regional hydraulic performances and radial forces exerted on the rotor.
The prototype successfully delivered flows of 0.5 to 3 lpm with pressure rises of 50 to 95 mmHg for 6000 to 10,000 RPM. Axial fluid forces reached values of 1N, and radial forces remained small for centered impeller position, as expected, and less than 1N for the off-centered impeller positions.
This prototype demonstrated excellent hydraulic performance with a mechanical suspension; the final magnetic suspension and motor design is underway.Copyright © 2005 by the American Society for Artificial Internal Organs