【作者】 陈刚；

【导师】 姚立纲；

【作者基本信息】 福州大学 ， 机械设计及理论， 2021， 博士

【摘要】 心室辅助装置是治疗心力衰竭的有效途径。磁悬浮血泵具有无接触、无摩擦、无污染等优点,目前广泛应用于心室辅助装置,近年来已成为人工器官领域的研究热点。论文针对机械接触式轴承章动血泵存在的缺陷,融合永磁悬浮和章动磁耦合传动的优点,提出并设计了一种永磁悬浮支承的无接触磁耦合驱动章动血泵,对血泵拓扑结构、章动永磁轴承承载特性、转子悬浮稳定性、血泵流场特性与血液损伤,以及磁悬浮章动血泵性能实验等展开研究。在章动传动和非接触磁力传动理论框架下,提出章动血泵永磁轴承支承和无接触磁耦合驱动基本原理,设计了永磁悬浮磁耦合驱动章动血泵的拓扑结构。根据等效磁荷理论,提出一种章动永磁体磁力解析计算模型,推导了永磁环章动过程的磁力解析式,并开展了章动磁力轴承承载力计算,揭示了章动角和悬浮气隙对章动永磁悬浮轴承承载特性的影响规律。通过对永磁悬浮章动血泵转子的承载力和承载刚度计算,分析了静态下转子承受外载荷的特性,表明血泵转子在静态下承受轴向外载荷可以稳定悬浮,但无法承受外力矩。进一步,基于章动转子的运动状态建立了永磁悬浮章动转子的有限元模型,探究了影响血泵转子动态悬浮稳定性的因素,揭示了章动血泵结构参数、永磁轴承尺寸和驱动磁体等关键因素对血泵转子悬浮稳定性的影响及其规律。基于CFD动网格更新方法建立了血泵数值计算模型,推导了血泵转子绕定坐标轴的转动角速度,模拟了血泵的水力性能和内部压力场、速度场以及剪切应力分布情况及其规律。建立了基于幂律模型的章动血泵血液损伤计算模型,将血液中红细胞作为血浆中的离散相,模拟血泵内红细胞受到的剪切应力、暴露时间以及运行轨迹,进而预测了磁悬浮章动血泵对红细胞的破坏程度。设计并研制了永磁悬浮磁耦合驱动章动血泵,搭建了血泵性能测试平台。重点对研制的血泵样机开展了水力性能测试、血泵功率消耗测试,血泵悬浮状态对比实验以及体外溶血测试。研究结果表明,将永磁悬浮支承和无接触磁耦合驱动引入章动血泵,可实现非接触支承和传动,有利于提高血泵血液相容性和传动稳定性。更多还原

【Abstract】 The ventricular assist device is an effective way to treat heart failure.As a core component of the ventricular assist device,the magnetic levitation blood pump has the advantages of non-contact,no friction,and no pollution during working.In recent years,it has become a research hotspot in the field of artificial organs.To overcome the defect of large frictional wearing appeared in traditional mechanical nutation blood pumps,we designed a new maglev nutation blood pump featured with the contactless magnetic coupling drive and the permanent magnetic levitation support.And then we studied the loading capacity of nutation magnetic bearing,the rotor levitated stability,and flow field characteristics of our designed blood pump.In the end,a testing experiment was completed to verify the performance of our designed blood pump.Based on the theory of nutation drive and non-contact magnetic transmission,the basic principles of permanent magnetic bearing and contactless magnetic coupling drive were proposed.The topology of the permanent maglev contactless magnetic coupling drive for a nutation blood pump was designed.According to the equivalent magnetic charge theory,an analytical calculation model of the magnetic force between nutating permanent magnetic rings was proposed.Meanwhile,the analytical formula of the magnetic force between nutating magnetic rings was deduced.Then,the loading capacity of the nutation magnetic bearing was calculated based on the analytical formula of magnetic forces.The effects of nutation angle and suspension air gap on the bearing characteristics of the nutating permanent magnetic bearing were revealed.The static bearing characteristics of the rotor under external load were studied through the calculations of the bearing capacity and bearing stiffness of the magnetic nutation rotor.Results showed that the rotor under the appliance of static external axial load can be suspended stably,except that of any external torque.Further,a dynamic finite element model of the permanent magnetic levitation nutation rotor was established.The factors that affect the dynamic suspension stability of the blood pump rotor were analyzed,and the obtained influences of the key factors such as structural parameters,magnetic bearing dimensions,and driving magnet on the suspension stability of the pump rotor were revealed.A numerical grid calculation model of the blood pump was established based on the dynamic grid updating method of CFD.The rotational angular velocity of the blood pump rotor around the fixed coordinate axis was deduced.The distributions of internal pressure,velocity,and shear stress in the blood pump as well as the pump’s hydraulic performance were calculated.The calculation model of blood injury in the nutation blood pump based on the Power-Law model was established.Taking the red blood cells in blood as the discrete-phase material in plasma,the running track,shear stress,and exposure time of red blood cells were calculated.Eventually,the damage extent of red blood cells in blood pump was predicted.Finally,a performance testing platform of the blood pump was built.In this testing platform,hydraulic performance experiments,power consumption tests,the suspension state monitoring,and in-vitro hemolysis experiment were carried out.The results showed that the introduction of permanent magnetic suspension support and contactless magnetic coupling drive into nutation blood pump may fulfill the contactless,frictionless,and wear-free support and transmission,which were conducive to improve the transmission stability and blood compatibility of blood pump.更多还原