Overset meshing in combination with novel blended weak-strong fluid-structure interactions for simulations of a translating valve in series with a second valve

Mechanical circulatory support (MCS) devices can bridge the gap to transplant whilst awaiting a viable donor heart. The Realheart Total Artificial Heart is a novel positive-displacement MCS that generates pulsatile flow via bileaflet mechanical valves. This study developed a combined computational fluid dynamics and fluid-structure interaction (FSI) methodology for simulating positive displacement bileaflet valves. Overset meshing discretised the fluid domain, and a blended weak-strong coupling FSI algorithm was combined with variable time-stepping. Four operating conditions of relevant stroke lengths and rates were assessed. The results demonstrated this modelling strategy is stable and efficient for modelling positive-displacement artificial hearts.

机械循环支持（Mechanical circulatory support, MCS）装置可在患者等待合格供体心脏期间，作为心脏移植的过渡桥梁。Realheart全人工心脏是一种新型容积式机械循环支持装置，通过双叶机械瓣膜（bileaflet mechanical valves）产生搏动血流。本研究开发了一种结合计算流体动力学（computational fluid dynamics, CFD）与流固耦合（fluid-structure interaction, FSI）的方法，用于模拟容积式双叶机械瓣膜。研究采用重叠网格（Overset meshing）技术对流体域进行离散，并将混合强弱耦合流固耦合算法与变时间步长方法相结合。本研究评估了四种与冲程长度及运行速率相关的工况。结果表明，该建模策略用于容积式人工心脏建模时，具备良好的稳定性与效率。