Abstract: In order to study the effects of active speed modulation on the internal flow field and blood damages in the blood pumps, the CFD method was adopted to simulate the full flowpath internal flow of a blood pump under speed modulations. The combined numerical simulation of the lumped cardiovascular system mathematical model and the rotary blood pump model was used to obtain the ventricular and aortic pressures under the assisting of the blood pump, which were then set as the inlet and outlet boundary conditions of the blood pump in CFD simulations. The flow fields of blood pump under the constant speed and three types of asynchronous speed modulation waveforms, including sine, square and triangle waves, were analyzed, and the velocity distribution and shear stress distribution of the rotary blood pumps were obtained. The results show that the flow pulsation of blood pump is enhanced under speed modulations, which is a feasible scheme to restore the pulsation of the blood flow. Among the three speed modulation waveforms, the blood pump flow pulsation index is high and the shear stress in the blood pump is small under the sinusoidal speed modulation, which is a relatively ideal speed modulation waveform.

Key words: rotary blood pump, computational fluid dynamics(CFD), speed modulation, cardiovascular system, pulsation index

摘要： 为研究血泵主动转速调节对血泵内部流场以及血液损伤的影响，采用计算流体动力学(CFD)方法模拟血泵在转速调制下的全流道内部流动。通过集总心血管系统数学模型和旋转血泵模型的联合数值模拟得到血泵辅助条件下的心室和主动脉压力，并设置为血泵CFD模拟的进出口边界条件。分析了匀转速以及正弦波、方波、三角波三种异步转速调制波形下的血泵流场情况，得到了旋转血泵的速度分布图以及剪切应力分布图。结果表明，转速调制下血泵的流量脉动得到了增强，是一种恢复血流搏动性的可行方案。三种速度调制波形中，正弦波转速调制下的血泵流量脉动指数高且血泵内剪切应力小，是相对理想的转速调制波形。

关键词: 旋转血泵, 计算流体动力学, 转速调制, 心血管系统, 脉动性指数