Current researches show that the constant speed mode adopted by the existing commercial blood pump may cause damage to the body. The way to solve this problem is to produce pulsating flow by changing the speed of the blood pump’s impeller. But at present, the flow field of the blood pump is not clear, when it changes speed, and the coupling between blood pump and body has not been considered in the simulation of the flow field. A multiscale coupling model combining hemodynamics (0D) and Computational Fluid Dynamics (3D) was established in this paper to solve the problem, and a speed change curve consistent with the ventricular motion was selected. The hemodynamics, shear stress, and hemolysis changes of 6000 rpm at different amplitude (2000, 3000, and 4000 rpm) were simulated, analyzed, and compared with the constant speed (7000 rpm). The results show that the pressure difference obtained by simulation is consistent with the experimental results, and the flow generated by the natural heart still flows through the blood pump, thus changing the working point of the blood pump. When the blood pump works at the changing speed, it could produce more pulsation, and the shear stress and hemolysis in the blood pump increase with the rising of speed and flow. But according to the hemolysis score of a single cardiac cycle, the hemolysis value of the changing speed model at an amplitude of 4000 rpm is only 11.71% higher than that of constant speed at 7000 rpm.

中文翻译：

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基于多尺度耦合模型的恒压和脉动速度下的血泵剪切应力和溶血分析

当前的研究表明，现有商用血泵采用的恒速模式可能会对人体造成伤害。解决该问题的方法是通过改变血泵叶轮的速度来产生脉动流。但是目前，当速度变化时，血泵的流场还不清楚，在模拟流场时还没有考虑到血泵与人体之间的耦合。为解决该问题，建立了一种将血液动力学（0D）和计算流体动力学（3D）相结合的多尺度耦合模型，并选择了与心室运动相一致的速度变化曲线。模拟，分析并分析了不同幅度（2000、3000和4000 rpm）下6000 rpm的血液动力学，剪切应力和溶血变化，并将其与恒定速度（7000 rpm）进行比较。结果表明，通过仿真得到的压差与实验结果一致，自然心脏产生的血流仍流经血泵，从而改变了血泵的工作点。当血泵以变化的速度工作时，它可能会产生更多的脉动，并且随着速度和流量的增加，血泵中的剪切应力和溶血现象会增加。但是，根据单个心动周期的溶血分数，变速模型在4000 rpm振幅下的溶血值仅比7000 rpm恒定速度下的溶血值高11.71％。当血泵以变化的速度工作时，它可能会产生更多的脉动，并且随着速度和流量的增加，血泵中的剪切应力和溶血现象会增加。但是，根据单个心动周期的溶血评分，变速模型在4000 rpm振幅下的溶血值仅比7000 rpm恒定速度下的溶血值高11.71％。当血泵以变化的速度工作时，它可能会产生更多的脉动，并且随着速度和流量的增加，血泵中的剪切应力和溶血现象会增加。但是，根据单个心动周期的溶血评分，变速模型在4000 rpm振幅下的溶血值仅比7000 rpm恒定速度下的溶血值高11.71％。