Numerical Simulation and Structural Optimization of Internal Flow Field of Magnetic Levitation Centrifugal Blood Pump for Infants

目的：探讨一种应用于婴幼儿的磁悬浮离心式血泵内部流场和血液流动性能，并对叶轮结构进行优化，为磁悬浮离心式血泵的结构设计提供参考。方法：本研究采用计算流体动力学(CFD)技术，基于k-ω湍流模型，在ANSYS Fluent平台上对磁悬浮离心式血泵的内部流场特性进行数值模拟与分析。具体模拟工况设定为流量Q = 1 L/min，转速n = 2200 r/min，计算分析血泵内部的压力场、速度场及剪切应力分布特性，通过改变流量和转速条件评估血泵的水力性能。基于仿真结果对叶轮结构进行优化设计，并对优化后的结构进行仿真验证。通过对优化前后仿真结果的对比分析，验证优化方案的有效性。结果：CFD计算结果表明，优化前血泵流道压力场呈均匀分布；最大流速为6.42 m/s，位于叶轮尖端，95%的流域保持2~5 m/s的速度(低于6 m/s的溶血阈值)。叶轮的高剪切应力区域(>150 Pa)占比小于5%。水力特性符合Q-H负相关及转速正相关规律。优化后泵内最大流速降低14.5% (峰值5.49 m/s)，叶轮高剪切区占比缩减至1% (715 Pa峰值)，显著提高了血液相容性。结论：优化后无叶片尖角结构叶轮可以有效减少泵内大剪切应力区域分布，降低泵内发生溶血的概率，提升泵的溶血性能，证明了优化叶轮结构的有效性。Objective: To investigate hemodynamic characteristics and optimize impeller configuration in a magnetically levitated centrifugal blood pump for pediatric applications, establishing design guidelines for enhanced hematological performance. Methods: In this study, computational fluid dynamics (CFD) technology and k-ω turbulence model were used to numerically simulate and analyze the internal flow field characteristics of maglev centrifugal blood pump on ANSYS Fluent platform. The specific simulation conditions were set as flow Q = 1 L/min and speed n = 2200 r/min. The pressure field, velocity field and shear stress distribution characteristics inside the blood pump were calculated and analyzed, and the hydraulic performance of the blood pump was evaluated by changing the flow rate and speed conditions. The impeller structure is optimized based on the simulation results, and the optimized structure is verified by simulation. Through the comparative analysis of the simulation results before and after optimization, the effectiveness of the optimization scheme is verified. Results The CFD calculation results show that the pressure field of blood pump flow channel is evenly distributed before optimization. Maximum velocity of 6.42 m/s localized at impeller tips, while 95% flow domain maintained 2~5 m/s velocities (below 6 m/s hemolysis threshold). The high shear stress area (>150 Pa) of the impeller is less than 5%. The hydraulic characteristics are consistent with Q-H negative correlation and speed positive correlation. After optimization, the maximum flow rate in the pump is reduced by 14.5% (peak 5.49 m/s), the proportion of high shear zone in the impeller is reduced to 1% (peak 715 Pa), significantly improving blood compatibility. Conclusion: After optimization, the impeller without sharp Angle structure can effectively reduce the regional distribution of large shear stress in the pump, reduce the probability of hemolysis in the pump, and improve the hemolysis performance of the pump, which proves the effectiveness of optimizing the impeller structure.