CFD ANALYSIS OF HEARTQUESTTM LVAD

Abstract

The purpose of this study is to present some of the design aspects used to develop the clinical version of the HeartQuestTM LVAD, a magnetically-levitated centrifugal blood pump. A 3-dimensional computational fluid dynamic (CFD) model of the HeartQuestTM LVAD including inlet and outlet was developed using Tascflow software (AEA Technology.) Detailed flow characteristics throughout the pump were simulated, providing blood velocity, pressure distribution, and shear stresses at several operating conditions. Initial results revealed a leading edge vortex within the inlet of the pump, extending into the leading edge of the impeller. Calculation of shear stress indicated regions of the flow, particularly along the blade tips, which may be susceptible to blood damage. These results were used to modify the flow path design. Additional simulation within the magnetic clearance regions were performed to assure shear stress and exposure were within satisfactory limits. Modifications to the dimensions were made to satisfy these requirements while minimizing loss of volumetric efficiency. Calculation of the fluid dynamic forces on the impeller provided essential data for the design of the magnetic levitation system. In summary, the CFD model has proved invaluable for designing both the blood flow paths and the magnetic suspension system.