Numerical Optimization of the Hydraulic and Hemolytic Performance of a Centrifugal Ventricular Assist Device Based on Impeller Flow Passage and Outlet Geometry

As technology continues to advance and modern lifestyles become increasingly mechanized, the prevalence of heart disease is steadily growing. On the other hand, donor hearts ready for transplantation are limited worldwide. Therefore, blood pumps are a suitable alternative to help the patient during the waiting period and even until the end of life. Blood pumps must meet biological requirements, including adequate output pressure and flow rate, within an acceptable margin of safety in the event of blood damage. Reduction of pump size, blood exposure time, and blood damage such as hemolysis have been mentioned as important challenges in the design of blood pumps. Statistics show that 30% of the patients who use a left ventricular blood pump need a right ventricular blood pump due to right ventricular failure. The purpose of this research is to determine the effect of the geometrical shape of the impellers (flow passage) and the thrust tube geometry of the volute chamber on the pump's hydraulic performance, the amount of axial and radial forces, and the amount of blood damage. So, for this study, six blades and two types of geometry for the volute chamber thrust tube were designed. This pump has been simulated using computational fluid dynamics used the Ansys CFX 17. Finally, the appropriate pump has been selected for low hemolysis index (HI). The HI calculated using the Lagrangian method is 0.00279 in the pump with a flow rate of 5 L per minute and 1100 rpm.