The development of blood-handling medical devices, such as ventricular assist devices, requires the analysis of their biocompatibility. Among other aspects, this includes hemolysis, i.e., red blood cell damage. For this purpose, computational fluid dynamics (CFD) methods are employed to predict blood flow in prototypes. The most basic hemolysis models directly estimate red blood cell damage from fluid stress in the resulting flow field. More advanced models explicitly resolve cell deformation. On the downside, these models are typically written in a Lagrangian formulation, i.e., they require pathline tracking. We present a new Eulerian description of cell deformation, enabling the evaluation of the solution across the whole domain. The resulting hemolysis model can be applied to any converged CFD simulation due to one-way coupling with the fluid velocity field. We discuss the efficient numerical treatment of the model equations in a stabilized finite element context. We validate the model by comparison to the original Lagrangian formulation in selected benchmark flows. Two more complex test cases demonstrate the method's capabilities in real-world applications. The results highlight the advantages over previous hemolysis models. In conclusion, the model holds great potential for the design process of future generations of medical devices.

翻译：血液处理医疗设备（如心室辅助装置）的开发需要对其生物相容性进行分析，其中涉及溶血（即红细胞损伤）问题。为此，计算流体动力学（CFD）方法被用于预测原型中的血液流动。最基本的溶血模型直接从流动场中的流体应力估算红细胞损伤，而更先进的模型则显式解析细胞变形。然而，这类模型通常采用拉格朗日公式编写，即需进行迹线追踪。本文提出了一种新的细胞变形欧拉描述方法，可实现在整个域内评估解。得益于与流体速度场的单向耦合，所得溶血模型可适用于任何收敛的CFD模拟。我们讨论了在稳定有限元框架下对该模型方程进行高效数值处理的方法。通过将模型与选定基准流动中的原始拉格朗日公式对比，验证了其有效性。两个更复杂的测试案例展示了该方法在实际应用中的能力。结果凸显了该模型相较于先前溶血模型的优势。结论表明，该模型在未来医疗设备的设计流程中具有巨大潜力。