Purpose

Rotary blood pumps (RBPs) employed as ventricular assist devices are developed to support the ventricles of patients suffering from heart failure. Computational Fluid Dynamics (CFD) is frequently used to predict the performance and haemocompatibility of these pumps during development, however different simulation techniques employed by various research groups result in inconsistent predictions. This inconsistency is further compounded by the lack of standardised model validation, thus it is difficult to determine which simulation techniques are accurate. To address these problems, the US Food and Drug Administration (FDA) proposed a simplified centrifugal RBP benchmark model. The aim of this paper was to determine simulation settings capable of producing accurate predictions using the published FDA results for validation.

Methods

This paper considers several studies to investigate the impact of simulation options on the prediction of pressure and flow velocities. These included evaluation of the mesh density and interface position through steady simulations as well as time step size and turbulence models (k-ε realizable, k-ω SST, k-ω SST Intermittency, RSM ω-based, SAS and SBES) using a sliding mesh approach.

Results

The most accurate steady simulation using the k-ω turbulence model predicted the pressure to within 5% of experimental results, however experienced issues with unphysical velocity fields. A more computationally expensive transient simulation that used the Stress-Blended Eddy Simulation (SBES) turbulence model provided a more accurate prediction of the velocity field and pressure rise to within experimental variation.

Conclusion

The findings of the study strongly suggest that SBES can be used to better predict RBP performance in the early development phase.

中文翻译：

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经验证的模拟离心血泵指南

目的

用作心室辅助装置的旋转血泵 (RBP) 被开发用于支持心力衰竭患者的心室。计算流体动力学 (CFD) 经常用于在开发过程中预测这些泵的性能和血液相容性，但是各个研究小组采用的不同模拟技术会导致预测不一致。由于缺乏标准化的模型验证，这种不一致进一步加剧，因此很难确定哪种模拟技术是准确的。为了解决这些问题，美国食品和药物管理局 (FDA) 提出了一种简化的离心 RBP 基准模型。本文的目的是确定能够使用已发布的 FDA 结果进行准确预测的模拟设置。

方法

本文考虑了多项研究，以研究模拟选项对压力和流速预测的影响。这些包括通过稳定模拟以及时间步长和湍流模型（k - ε可实现、k - ω SST、k - ω SST 间歇性、RSM ω -based、SAS 和 SBES）评估网格密度和界面位置滑动网格方法。

结果

使用k - ω湍流模型的最准确的稳态模拟预测压力在实验结果的 5% 以内，但是遇到了非物理速度场的问题。使用应力混合涡流模拟 (SBES) 湍流模型的计算成本更高的瞬态模拟提供了对实验变化范围内的速度场和压力上升的更准确预测。

结论

该研究的结果强烈表明，SBES 可用于更好地预测早期开发阶段的 RBP 性能。