Dynamic characteristics of a magnetically levitated impeller in a centrifugal blood pump.
Dynamic characteristics of a magnetically levitated impeller in a centrifugal blood pump.
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DOI：
10.1111/j.1525-1594.2007.00378.x
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发表时间：
2007-04
影响因子：
2.4
通讯作者：
J. Asama;T. Shinshi;H. Hoshi;S. Takatani;A. Shimokohbe
中科院分区：
文献类型：
--
作者：
J. Asama;T. Shinshi;H. Hoshi;S. Takatani;A. Shimokohbe
已经开发了采用混合主动/被动磁轴承来支撑非接触式叶轮的离心血泵，以减少轴承磨损、泵尺寸、主动磁轴承的功耗和血液创伤。然而，在设计阶段对泵运行期间叶轮在被动悬挂方向上的振动进行的估计是不准确的，因为泵送流体和叶轮旋转对动态特性的影响没有得到充分认识。本研究的目的是研究磁悬浮旋转叶轮的流体中的动态特性，通过测量在宽频率范围内对壳体的正弦激励的频率响应和由于在左心室（LV）辅助期间输入脉动流而引起的位移。激振试验是在叶轮悬浮在空气或水中，旋转或不旋转的条件下进行的。实验和分析结果表明，叶轮在水中受外力作用时的振动比在空气中受水压力作用时的振动小。轴向谐振频率与转速成二次方关系上升，由于陀螺效应，旋转时倾斜模有两个谐振频率。将泵插入模拟体循环回路中，在LV辅助期间施加脉动压力时叶轮的动态稳定性通过实验进行验证。响应于被动约束方向上的脉动流的振动幅度在尺寸上比叶轮和泵壳体之间的初始间隙的尺寸小得多。
Centrifugal blood pumps that employ hybrid active/passive magnetic bearings to support noncontact impellers have been developed in order to reduce bearing wear, pump size, the power consumption of the active magnetic bearing, and blood trauma. However, estimates made at the design stage of the vibration of the impeller in the direction of passive suspension during pump operation were inaccurate, because the influence of both the pumping fluid and the rotation of the impeller on the dynamic characteristics was not fully recognized. The purpose of this study is to investigate the dynamic characteristics in a fluid of a magnetically levitated rotating impeller by measuring both the frequency response to sinusoidal excitation of the housing over a wide frequency range and the displacement due to input of a pulsatile flow during left ventricular (LV) assist. The excitation tests were conducted under conditions in which the impeller was levitated in either air or water, and with or without rotation. The experimental and analytical results indicate that vibration of the impeller due to the external force in water was decreased, compared with that in air due to the hydraulic force of water. The axial resonant frequency rose quadratically with rotational speed, and the tilt mode had two resonant frequencies while rotating due to the gyroscopic effect. With the pump inserted into a mock systemic circulatory loop, the dynamic stability of the impeller when pulsatile pressure was applied during LV assist was verified experimentally. The amplitudes of vibration in response to the pulsatile flow in the passively constrained directions were considerably smaller in size than the dimensions of initial gaps between the impeller and the pump housing.