Computational modelling of flow through prosthetic heart valves using the entropic lattice-Boltzmann method

Previous clinical, in vitro experimental and in silico simulation studies have shown the complex dynamics of flow through prosthetic heart valves. In the case of bileaflet mechanical heart valves (BMHVs), complex flow phenomena are observed due to the presence of two rigid leaflets. A numerical method for this type of study must be able to accurately simulate pulsatile flow through BMHVs with the inclusion of leaflet motion and high-Reynolds-number flow modelling. Consequently, this study aims at validating a numerical method that captures the flow dynamics for pulsatile flow through a BMHV. A 23 mm St. Jude Medical (SJM) Regent (TM) valve is selected for use in both the experiments and numerical simulations. The entropic lattice-Boltzmann method is used to simulate pulsatile flow through the valve with the inclusion of reverse leakage flow, while prescribing the flowrate and leaflet motion from experimental data. The numerical simulations are compared against experimental digital particle image velocimetry (DPIV) results from a previous study for validation. The numerical method is shown to match well with the experimental results quantitatively as well as qualitatively. Simulations are performed with efficient parallel processing at very high spatiotemporal resolution that can capture the finest details in the pulsatile BMHV flow field. This study validates the lattice-Boltzmann method as suitable for simulating pulsatile, high-Reynolds-number flows through prosthetic devices for use in future research.