Abstract：In order to solve the problems of hemolysis and thrombosis caused by tip clearance leakage in blood pumps, this article introduces a folded unequal spacing impeller, using CFD technology to conduct numerical simulation of the internal flow field, and unequal spacing from the non-folded impeller. The impeller and the flanged equally spaced impeller were comparatively analyzed, and their internal flow field dynamic characteristics and blood compatibility were studied. The results show that the folded impeller structure blood pump avoids the generation of leakage flow in the tip gap of the impeller, while the folded 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 percentage of the wall shear stress of the folded unequally spaced impeller blood pump in the range of 0-150 Pa reaches 96.84%, the exposure time is relatively concentrated and meets the design requirements of an artificial blood pump; and the hemolysis value decreases by 3.50% compared with the non-folding unequally spaced impeller blood pump and by 12.72% compared with the folded equally spaced impeller blood pump, and the hemolysis performance is optimal. The proposed folded-edge unequally spaced impeller blood pump can effectively reduce the probability of red blood cell breakage and the occurrence of hemolysis and thrombosis, which can provide some reference for the structural design and optimization of axial blood pumps.
