基于正弦转速调制的离心旋转血泵温度场分析

为研究转速调制引起的血泵内部流场温度变化是否会导致血液损伤，应用计算流体动力学方法对旋转血泵运行时的全流道流动过程进行数值模拟.计算中采用动态压力拟合公式作为进出口边界条件，选择在换热领域精确度更高的SST湍流模型.计算叶轮分别在匀转速状态和正弦调制转速状态下不同时刻的温度分布、温度升高到39～43℃时的潜在高温风险区域以及大于43℃时的极端高温风险区域在血泵中的位置分布和各区域的体积大小，同时结合血泵结构对比分析其内部的动态温升变化情况.研究结果表明：血泵流场在正弦调制转速时的温升高于匀转速状态下的流场，并产生高温风险区域；温升与血泵的叶轮结构密切相关，高温集中在靠近下泵壳的叶轮前缘和内侧；2种转速工况对血泵进出口处的血液温度影响均在2℃的安全浮动范围内，不会对血泵外部的血液造成损伤.

Temperature field analysis of centrifugal rotary blood pump based on sinusoidal speed modulation

In order to study whether the temperature change of the internal flow field the blood pump under sinusoidal speed modulation will cause blood damage, computational fluid dynamics method was used to simulate the whole dynamic flow process of the blood pump. The inlet and outlet dynamic pressure fitting formula were adopted as boundary conditions. The SST turbulence model with higher accuracy in heat transfer field for numerical simulation. The temperature distribution cloud diagrams of the impeller at different time under constant and sinusoidal speeds were obtained. The distribution of the potential risk area with temperature reaching 39-43 ℃ and the risk area with temperature greater than 43 ℃ in the blood pump were obtained, the volume of each area calculated. At the same time, the dynamic temperature rise inside the blood pump compared and analyzed combined with the blood pump′s structure. The results show that the temperature rise inside the blood pump under the sinusoidal speed modulation is higher than that under the constant speed mode, risk region. The temperature rise is closely related to the impeller′s structure of the blood pump, and the high temperature is concentrated at the front edge and inner sides of the impeller near the lower pump housing. The blood temperature rise at the inlet and outlet under both conditions within the safe range of 2 ℃, would not cause damage to the blood outside the blood pump.