Mechanism for cavitation in the mechanical heart valve with an artificial heart: nuclei and viscosity dependence.
Mechanism for cavitation in the mechanical heart valve with an artificial heart: nuclei and viscosity dependence.
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DOI：
10.1111/j.1525-1594.2004.29001.x
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发表时间：
2005
影响因子：
2.4
通讯作者：
Hwansung Lee;Y. Taenaka;S. Kitamura
中科院分区：
文献类型：
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作者：
Hwansung Lee;Y. Taenaka;S. Kitamura
到目前为止，我们已经估计了机械心脏瓣膜（MHV）安装在电动液压全人工心脏（EHTAH）与自来水的空化。然而，室温下的自来水并不是37摄氏度血液的适当替代品。因此，我们调查的MHV空化与粘度和核含量的测试流体的研究中的流体特性。我们使用了安装在EHTAH二尖瓣位置的Medtronic Hall瓣膜。作为测试流体，使用自来水、蒸馏水和甘油溶液。采用阀门关闭速度、压力降测量和高速摄像机来确定MHV中的空化强度。汽蚀气泡主要出现在阀挡边缘。我们对结果的分析表明，挤压流是Medtronic Hall阀中气穴的主要原因。汽蚀强度随流体粘度和阀门关闭速度的增大而增大。即使在甘油溶液中的空化强度较大，在甘油溶液中发生空化的概率也比在自来水中小。我们的研究结果表明，自来水中含有颗粒，导致空化发生概率增加。结果表明，空化强度受流体中的核浓度和流体粘度的影响很大。
Until now, we have estimated cavitation for mechanical heart valves (MHV) mounted in an electrohydraulic total artificial heart (EHTAH) with tap water. However, tap water at room temperature is not a proper substitute for blood at 37 degrees C. We therefore investigated fluid characterization in studies of MHV cavitation associated with the viscosity and nuclei content of a testing fluid. We used the Medtronic Hall valve mounted in the mitral position of the EHTAH. As testing fluids, tap water, distilled water, and glycerin solution were used. The valve-closing velocity, pressure-drop measurements, and a high-speed video camera were employed to determine the cavitation intensity in MHV. Most of the cavitation bubbles were observed at the edge of the valve stop. Our analysis of the results indicates that squeeze flow is the major cause of cavitation in the Medtronic Hall valve. The cavitation intensity increased with increases in the fluid viscosity and the valve-closing velocity. Even if cavitation intensity in glycerin solution was greater, the cavitation occurrence probability was less in glycerin solution than in tap water. Our results suggest that tap water contains particles that cause an increase in the cavitation occurrence probability. We conclude that cavitation intensity is greatly affected by the nuclei concentration in the fluid and the fluid viscosity.