基于数值模拟的混流式血泵结构改进

Structure improvement of mixed flow blood pump based on numerical simulation

轴流式血泵转速过高、离心式血泵易产生流动死区是造成血液损伤的重要原因,而混流式血泵能有效缓解转速过高及流动死区问题。基于此,采用计算流体力学方法对闭式叶轮混流式血泵进行了三维流场仿真,分别探究了不同叶片数和叶片厚度的混流式血泵的性能,分析了血泵流场特性及压力分布情况;基于溶血幂函数模型,通过拉格朗日粒子追踪法进行血泵的溶血性能预测,得到水力性能与溶血性能良好的血泵结构参数。结果表明,当叶片数为5、叶片厚度为0.8 mm时,扬程更接近预期设计目标,能够满足血泵供压需求;溶血指数比原模型降低14.65%,有效降低溶血程度;内部流场均匀稳定,未出现回流、流动死区问题,有效防止血栓产生;叶片进口处低压区域减少,有效缓解空化现象产生。研究结果可为闭式叶轮混流式血泵的结构改进及性能改善提供依据。

The high rotational speed of the axial flow blood pump and flow separation of the centrifugal blood pump are the leading causes of blood damage in the blood pump. Nevertheless, the mixed flow blood pump can effectively alleviate the high rotational speed and the flow separation. Based on this, the three-dimensional flow simulation of a closed impeller mixed flow blood pump was carried out by the computational fluid dynamics method. The blood pump performance with different blade numbers and thicknesses was investigated. The blood pump flow characteristics and pressure distribution were analyzed. Based on the hemolysis power function model, the Lagrangian particle tracking method was used to predict the blood pump hemolysis performance. The structural parameters with excellent hydraulic performance and hemolysis performance were obtained. The results show that the lift is closer to the expected design target when the number of the blades is 5, and the thickness is 0.8 mm, which ensures the pressure demand of the blood pump. The hemolytic index is reduced by 14.65%, and the thrombosis is effectively reduced. There is no backflow or flow fixed vortex zone due to uniform and stable internal flow. The cavitation intensity is effectively alleviated due to the reduction of low-pressure area at the blade entrance. The research results may provide a basis for the structural improvement and performance evaluation of the closed impeller mixed flow blood pump.