Abstract：
This study uses CFD methods to investigate the effects of the impeller\'s geometry on the hemodynamic characteristics, pump performance, and blood damage parameters, in a percutaneous microaxial Mechanical Circulatory Support (MCS) device. The numerical simulations employ the steady state Reynolds-Averaged Navier-Stokes approximation using the SST k-ω turbulent model. Three different impeller models are examined with different hub conversion angles (α = 0○, 3○ and 5○). The analysis includes 23 cases for different pressure heads (Δp = 60-80 mmHg) and angular velocities (ω = 30-52 kRPM). The obtained flow rate is compared between the cases to assess the effect of the impeller\'s design and working conditions on the pump performance. The comparative risk of shear-induced platelet activation is estimated using the statistical median of the stress-accumulation values calculated along streamlines. The risk of hemolysis is estimated using the average exposure time to shear stress above a threshold (τ > 425 Pa). The results reveal that the shape of the impeller\'s hub has a great impact on the flow patterns, performance, and risk of blood damage, as well as the angular velocity. The highest flow rate (Q = 3.7 L/min) and efficiency (η = 11.3 %) were achieved using a straight hub (α = 0○). Similarly, for the same condition of flow and pressure, the straight hub impeller has the lowest blood damage risk parameters. This study shed light on the effect of pump design on the performance and risk of blood damage, indicating the roles of the hub shape and angular velocity as dominant parameters.
摘要：
本研究采用CFD方法研究叶轮几何形状对血流动力学特性的影响,泵性能,和血液损伤参数，在经皮微轴向机械循环支持（MCS）装置。数值模拟采用SSTk-ω湍流模型的稳态雷诺平均Navier-Stokes近似。以不同的轮毂转换角度(α=0○，3○和5○)。分析包括23种不同压头（Δp=60-80mmHg）和角速度（ω=30-52kRPM）的情况。在两种情况下比较获得的流量，以评估叶轮的设计和工作条件对泵性能的影响。使用沿流线计算的应力累积值的统计中值来估计剪切诱导的血小板活化的比较风险。使用高于阈值(τ>425Pa)的剪切应力的平均暴露时间来估计溶血风险。结果表明,叶轮轮毂的形状对其流型有很大的影响,性能，和血液受损的风险，以及角速度。使用直轮毂(α=0〇)实现了最高流量(Q=3.7L/min)和效率(η=11.3%)。同样，对于相同的流量和压力条件，直轮毂叶轮的血损风险参数最低。这项研究揭示了泵设计对性能和血液损伤风险的影响，指示轮毂形状和角速度作为主要参数的作用。
