BACKGROUND:Computational fluid dynamics (CFD) is an important tool for predicting cardiovascular device performance. The FDA developed a benchmark nozzle model in which experimental and CFD data were compared, however, the studies were limited by steady flows and Newtonian models. OBJECTIVE:Newtonian and non-Newtonian blood models will be compared under steady and pulsatile flows to evaluate their influence on hemodynamics in the FDA nozzle. METHODS:CFD simulations were validated against the FDA data for steady flow with a Newtonian model. Further simulations were performed using Newtonian and non-Newtonian models under both steady and pulsatile flows. RESULTS:CFD results were within the experimental standard deviations at nearly all locations and Reynolds numbers. The model differences were most evident at Re = 500, in the recirculation regions, and during diastole. The non-Newtonian model predicted blunter upstream velocity profiles, higher velocities in the throat, and differences in the recirculation flow patterns. The non-Newtonian model also predicted a greater pressure drop at Re = 500 with minimal differences observed at higher Reynolds numbers. CONCLUSIONS:An improved modeling framework and validation procedure were used to further investigate hemodynamics in geometries relevant to cardiovascular devices and found that accounting for blood’s non-Newtonian and pulsatile behavior can lead to large differences in predictions in hemodynamic parameters.

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非牛顿血液模型和脉动对食品和药物管理局基准喷嘴模型中血液动力学的影响

背景：计算流体动力学 (CFD) 是预测心血管设备性能的重要工具。FDA 开发了一个基准喷嘴模型，在该模型中比较了实验数据和 CFD 数据，但是，研究受到稳态流和牛顿模型的限制。目标：牛顿和非牛顿血液模型将在稳态和脉动流下进行比较，以评估它们对 FDA 喷嘴中血液动力学的影响。方法：CFD 模拟针对使用牛顿模型的稳定流的 FDA 数据进行了验证。在稳态和脉动流下使用牛顿和非牛顿模型进行了进一步的模拟。结果：几乎所有位置和雷诺数的 CFD 结果都在实验标准差范围内。在再循环区域，模型差异在 Re = 500 时最为明显，和舒张期。非牛顿模型预测了较钝的上游速度分布、喉道中较高的速度以及再循环流动模式的差异。非牛顿模型还预测在 Re = 500 时会有更大的压降，而在较高的雷诺数下观察到的差异最小。结论：使用改进的建模框架和验证程序进一步研究与心血管设备相关的几何形状中的血液动力学，发现考虑血液的非牛顿和脉动行为可能导致血液动力学参数预测的巨大差异。非牛顿模型还预测在 Re = 500 时会有更大的压降，而在较高的雷诺数下观察到的差异最小。结论：使用改进的建模框架和验证程序进一步研究与心血管设备相关的几何形状中的血液动力学，发现考虑血液的非牛顿和脉动行为可能导致血液动力学参数预测的巨大差异。非牛顿模型还预测在 Re = 500 时会有更大的压降，而在较高的雷诺数下观察到的差异最小。结论：使用改进的建模框架和验证程序进一步研究与心血管设备相关的几何形状中的血液动力学，发现考虑血液的非牛顿和脉动行为可能导致血液动力学参数预测的巨大差异。