Computational and experimental evaluation of the fluid dynamics and hemocompatibility of the CentriMag blood pump.

The CentriMag centrifugal blood pump is a newly developed ventricular assist device based on magnetically levitated bearingless rotor technology. A combined computational and experimental study was conducted to characterize the hemodynamic and hemocompatibility performances of this novel blood pump. Both the three-dimensional flow features of the CentriMag blood pump and its hemolytic characteristics were analyzed using computational fluid dynamics (CFD)-based modeling. The hydraulic pump performance and hemolysis level were quantified experimentally. The CFD simulation demonstrated a clean and streamlined flow field in the main components of the CentriMag blood pump. The predicted results by hemolysis model indicated no significant high shear stress regions in the pump. A comparison of CFD predictions and experimental results showed good agreements. The relatively large gap passages (1.5 mm) between the outer rotor walls and the lower housing cavity walls provide a very good surface washing through a secondary flow path while the shear stresses in the secondary flow paths are reduced, resulting in a low rate of hemolysis ([Normalized Index of Hemolysis] NIH = 0.0029 +/- 0.006) without a decrease of the pump's hydrodynamic performance (pressure head: 352 mm Hg at a flow rate of 5.0 L/min and a rotational speed of 4,000 rpm).