Numerical study on the performance of an interventional microaxial blood pump with superhydrophobic surface

Unlike traditional blood pumps, interventional microaxial blood pumps are characterized by their small size, high rotational speed, and narrow gap between the impeller rim and pump housing. These features result in an unstable flow field within the pump, leading to high shear stress regions that can cause hemolysis. To improve the hydraulic efficiency of the blood pump and mitigate blood damage, this paper proposes an interventional microaxial blood pump with a superhydrophobic surface. The finite element method was used to model the axial blood pump and arterial flow field, with Navier slip boundary conditions applied to the impeller and outflow structure walls, simulating a slip length of 50 μm to represent the superhydrophobic surface characteristics. A combination of numerical simulations and hydraulic experiments was employed to evaluate the effects of the superhydrophobic surface on the pump's hydraulic performance and hemolysis characteristics. The results indicated that the designed interventional microaxial blood pump model demonstrated good blood compatibility. The superhydrophobic surface significantly reduced shear stress at the design point, with wall shear stress in the impeller and outflow structure regions decreasing by approximately 8.09%. Hydraulic efficiency increased by approximately 12.16%, and the hemolysis index decreased by about 12.60%. These findings provide valuable support for further optimization of microaxial blood pumps.