标题： 多目标CFD优化用于PediaFlow儿科左心室辅助装置的中间扩压器级 显示英文标题

标题： Multi-objective CFD optimization of an intermediate diffuser stage for PediaFlow pediatric ventricular assist device

摘要： 背景：计算流体动力学（CFD）已成为心室辅助装置（VAD）设计的重要工具，其中最大化性能的目标常常与生物相容性发生冲突。由于较小的患者群体带来的严格尺寸限制，这种权衡在儿科应用中显得更加明显。本研究提出了一个自动化的CFD驱动的形状优化方法，用于新型中间扩散器阶段的优化，该阶段位于PediaFlow儿科VAD的叶轮下游，以提高压力恢复。方法：我们采用多目标优化方法，在最大化压力恢复的同时最小化溶血。所提出的扩散器阶段从整个流动域中分离出来，使得使用Sobol序列高效评估超过450种设计变体成为可能，这产生了非支配解的帕累托前沿。选定的最佳候选方案进一步使用局部T搜索算法进行优化。然后将优化后的前部扩散器整合到整个泵中进行CFD验证和体外验证。结果：我们识别出关键依赖关系，较长的叶片增加了压力恢复但同时也增加了溶血，而包裹角度与压力恢复呈强抛物线关系，与溶血呈单调关系。出乎意料的是，叶片较少（2-3片）的配置在两个指标上始终优于叶片较多（4-5片）的配置。优化的两叶片设计使泵在较低转速下运行（14,000 vs 16,000 RPM），提高了水力效率从26.3%到32.5%，并将溶血降低了31%。结论：这种方法表明，多目标CFD优化可以系统地探索复杂的设计空间，同时平衡儿科VAD的性能和血液相容性的竞争优先事项。 显示英文摘要

摘要： Background: Computational fluid dynamics (CFD) has become an essential design tool for ventricular assist devices (VADs), where the goal of maximizing performance often conflicts with biocompatibility. This tradeoff becomes even more pronounced in pediatric applications due to the stringent size constraints imposed by the smaller patient population. This study presents an automated CFD-driven shape optimization of a new intermediate diffuser stage for the PediaFlow pediatric VAD, positioned immediately downstream of the impeller to improve pressure recovery. Methods: We adopted a multi-objective optimization approach to maximize pressure recovery while minimizing hemolysis. The proposed diffuser stage was isolated from the rest of the flow domain, enabling efficient evaluation of over 450 design variants using Sobol sequence, which yielded a Pareto front of non-dominated solutions. The selected best candidate was further refined using local T-search algorithm. We then incorporated the optimized front diffuser into the full pump for CFD verification and in vitro validation. Results: We identified critical dependencies where longer blades increased pressure recovery but also hemolysis, while the wrap angle showed a strong parabolic relationship with pressure recovery but a monotonic relationship with hemolysis. Counterintuitively, configurations with fewer blades (2-3) consistently outperformed those with more blades (4-5) in both metrics. The optimized two-blade design enabled operation at lower pump speeds (14,000 vs 16,000 RPM), improving hydraulic efficiency from 26.3% to 32.5% and reducing hemolysis by 31%. Conclusion: This approach demonstrates that multi-objective CFD optimization can systematically explore complex design spaces while balancing competing priorities of performance and hemocompatibility for pediatric VADs.