背景:溶血现象是人工心脏泵设计与研发历程中的一个重要问题, 溶血的产生与血细胞在泵内运动时所受剪切力和在泵内的运动时间有关.目的:分析离心血泵不同运行参数及不同结构参数与血细胞在泵内所受剪切力之间的关系.方法:根据速度系数法设计离心血泵的基本结构;分别利用CFturbo、ANSYS ICEM与FLUENT软件建立血泵的三维模型, 网格划分与流场模拟, 以此研究出最佳的网格划分方法;再根据数值模拟的结果对叶轮出口直径进行修正, 最终得到符合人体心脏所需的人工心脏泵.以降低血细胞在心脏泵中所受切应力和运动时间为目的, 对离心式人工心脏泵结构参数叶轮入口流量Q (2, 3, 4, 5, 6, 7L/min) 、运行参数叶片出口宽度b2 (2.0, 2.1, 2.2, 2.3, 2.4, 2.5 mm) 进行优化设计与分析比较, 以期降低溶血现象发生的概率.结果与结论: (1) 随着流量的增加, 血细胞在血泵内受到的切应力逐渐增加, 运动时间逐渐减少.随着流量的增加, 血泵内的标准溶血值逐渐减小, 血细胞在血泵内受到的损伤越小;当流量取7 L/min时, 血泵内标准溶血值最低; (2) 随着叶片出口宽度的增大, 血液在泵内所受的切应力总体呈下降趋势, 血液在泵内的运动时间总体呈现增加趋势;当叶片出口宽度在2.0-2.5 mm范围内, 随着叶片出口宽度的增加, 血泵内的标准溶血值逐渐减小, 血细胞在血泵内受到的损伤越小, 当叶片出口宽度为2.5 mm左右时血泵内溶血值最低.%BACKGROUND: Hemolysis is an important problem in the design and development of artificial heart pumps. Hemolysis is associated with the shear force of blood cells in the pump and the movement time in the pump. OBJECTIVE: To analyze the relationship between the operating parameters of blood pump (flow rate of blood pump), the structure of blood pump (outlet width of blade) and the shear stress of blood cells in artificial heart pump. METHODS: The basic structure of the centrifugal blood pump was designed according to the velocity coefficient method. The three-dimensional model of the blood pump, mesh division and flow field simulation were established by using CFturbo, ANSYS ICEM and FLUENT software respectively to study the best mesh division method. The results of the numerical simulation corrected the diameter of the impeller outlet to finally obtain an artificial heart pump meeting the needs of the human heart. In order to reduce the shear stress and movement time of blood cells in the heart pump, the optimal design and analysis of the impeller inlet flow rate Q (2, 3, 4, 5, 6, 7 L/min) and the operating parameter blade outlet width b2 (2.0, 2.1, 2.2, 2.3, 2.4, 2.5 mm) of the centrifugal artificial heart pump were designed to reduce the probability of hemolysis. RESULTS AND CONCLUSION: (1) As the flow rate increased, the shear stress of the blood cells in the blood pump gradually increased, and the movement time gradually decreased. As the flow rate increased, the standard hemolysis value in the blood pump gradually decreased, and the damage to the blood cells in the blood pump alleviated. When the flow rate was 7 L/min, the standard hemolysis value in the blood pump was the lowest. (2) With the increase of blade outlet width, the shear stress of the blood in the pump decreased, and the movement time of the blood in the pump increased. When the blade outlet width was 2.0-2.5 mm, the hemolysis value in the blood pump decreased with the increase of the blade outlet width. When the blade outlet width was about 2.5 mm, the hemolysis value in the blood pump was the lowest.
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