计算流体力学方法分析一例喷射悬浮血泵的液力、悬浮及溶血特性

Computational Fluid Dynamics Analysis of an Injection Suspension Blood Pump on the Hydraulic, Suspension and Hemolysis Property

左心室辅助装置被用于治疗严重的心力衰竭,目前第三代左心室辅助装置采用液力悬浮或磁力悬浮手段,让转子悬浮在腔室中,从而完全避免机械磨损。然而,磁力悬浮需要主动控制和额外能耗,不利于长时间续航。而液力悬浮轴承间隙很小(通常小于100μm),在这一微小间隙中,会产生高切应力和滞流点,从而造成血液损伤。为此设计一种采用新型喷射悬浮手段的血泵。该悬浮手段为被动式,且几乎没有额外的能量损耗。运用流体力学方法分析这一血泵的液力、悬浮和血液相容性能,进行试验验证,并对比新型悬浮血泵和没有喷射流道的参照泵的血液相容性。研究显示,喷射悬浮方式可以在较大的间隙下有效实现转子悬浮,且具有良好的血液相容性,对左心室辅助装置的发展有重要意义。

Left ventricular assist devices(LVADs) have been developed to treat severe heart failure. Nowadays the third-generation LVADs apply either hydrodynamic or magnetic suspension method to avoid mechanical wearing. However, the magnetic suspension needs complex control system and extra energy consumption, which is not beneficial for long battery life. The hydrodynamic suspension occupies narrow gaps(usually less than 100 μm), where high shear stress and stagnant points would occur, which would cause blood damage. A blood pump using a novel injection suspension method to levitate the rotor is developed. The injection suspension method is passive and needs little extra energy consumption. The hydraulic, suspension and hemolysis property of the pump were investigated using CFD methods. Validation experiments are conducted. The hemolysis property of the novel pump and a reference pump without injection channels are compared. The results indicate that the injection suspension method could effectively levitate the rotor with a wider gap, and it has good hemocompatibility. The novel injection suspension method has important significance for the future LVAD development.