Numerical simulation of steady flow in a two-dimensional total artificial heart model

Area of Science:

• Biomedical Engineering
• Fluid Dynamics
• Computational Mechanics

Background:

• Total artificial hearts (TAHs) are crucial for end-stage heart failure treatment.
• Optimizing TAH internal flow dynamics is essential for device longevity and patient outcomes.
• Valve design significantly impacts flow patterns and potential complications like thrombus formation.

Purpose of the Study:

• To numerically simulate and compare flow dynamics in a 2D TAH model using different inflow valve designs.
• To evaluate the impact of trileaflet versus flap inflow valves on ventricular chamber flow patterns and turbulence.
• To correlate simulated flow characteristics with potential risks of thrombus formation.

Main Methods:

• Steady laminar and turbulent flow simulation using the finite analytic numerical method.
• Employed the k-epsilon-E model for turbulence closure and the SIMPLER algorithm for solving governing equations.
• Modeled a TAH with trileaflet outflow valves and either trileaflet or flap inflow valves.

Main Results:

• The flap inflow valve resulted in smaller regions of stasis and trapped vortices within the TAH chamber compared to the trileaflet inflow valve.
• Reynolds stresses distal to the inflow valve were lower with the flap valve.
• Simulated flow patterns showed good agreement with existing in vitro measurements.

Conclusions:

• Flap valve (or tilting disk valve) geometries promote superior flow dynamics within the TAH chamber compared to trileaflet valves.
• Reduced turbulent stresses associated with flap valves may decrease the risk of thrombus formation near TAH valves.
• Numerical simulations provide valuable insights for optimizing TAH design and valve selection.