Abstract:
In order to solve the problems of hemolysis and thrombosis caused by tip clearance leakage in axial flow blood pumps, a folded-edge unequally spaced impeller was introduced first, then CFD technology was used to simulate the internal flow field dynamic characteristics and blood compatibility. In addition, the results were compared with that of the non-folded-edge unequally spaced impeller and folded-edge equally spaced impeller. The results show that the blood pump with folded-edge impeller structure avoids the generation of leakage flow in the tip gap of the impeller, while the folded-edge unequally spaced impeller reduces the backflow and vortex at the inlet and outlet of the impeller, and the overall shear stress in the flow channel is lower than the other two impellers. The hemolysis index(HI) of all three impellers meets the hemolysis design index of the blood pump, in which the percen-tage of the wall shear stress of the blood pump with folded-edge unequally spaced impeller in the range of 0-150 Pa reaches 96.84%, the exposure time is relatively concentrated and the design requirements of an artificial blood pump are met. The hemolysis value decrease by 3.50% and 12.50%, respectively, while compared with blood pump with non-folded-edge unequally spaced impeller and folded-edge equally spaced impeller, and the hemolysis performance is optimal. The proposed blood pump with folded-edge unequally spaced impeller can effectively reduce the probability of red blood cell breakage and the occurrence of hemolysis and thrombosis, which can provide reference for the structural design and optimization of axial flow blood pumps.