Numerical and Experimantal Analysis of A New High-Speed Heart Assist Pump

Left Ventricular assist devices are used in patients with heart failure. There are three types of rotodynamic blood pumps: centrifugal, axial and mixed flow. Axial flow blood pumps have high speed but they have small diameter pumps. In this study, Pump characteristics were determined with the Computational Fluid Dynamics (CFD) software of a designed mixed-flow (semi-axial) blood pump and pump characteristics were experimentally verified. For the design point of the pump, 10000 rpm rotation speed, 5 L/min flow rate and 100 mm-Hg pressure difference values were selected. Pump design and solid modeling programs were used in the design of the pump impeller and diffuser. The pump having a solid model according to design data specified was analyzed with the ANSYS Fluent and verification of the initial design values was made. Depending on the flow rate, the pressure difference, torque, wall shear stress and yield were calculated by CFD. In addition, the pump performance was determined by CFD software separately for the case where the pump is driven by the shaft, the suction line and the discharge line. After optimization study with CFD, the final solid models of the impeller and the diffuser were generated. The prototypes of these two elements were produced by laser sintering technology. The pump casing was made from aluminum material at the CNC vertical machining center. The experimental performance of the prototype pump was determined by water and volume of 40% glycerin-60% water at the rotational speed providing design and design pressure difference. Flow-pressure difference curves were constituted using CFD and experimental outputs for water. It has been determined that the initial design value of the design point is less than 8 torr. According to CFD outputs; the presence of the shaft that drives the pump impeller on the suction line or the discharge line has no effect on the pressure difference and the flow line