Flow visualization in an artificial heart using diffuse and planar laser lighting

Area of Science:

• Biomedical Engineering
• Fluid Dynamics
• Cardiovascular Science

Background:

• Artificial heart devices are critical for patients with end-stage heart failure.
• Understanding internal flow dynamics is essential for optimizing artificial heart performance and biocompatibility.

Purpose of the Study:

• To characterize the complex flow properties within a clinical pusher plate type artificial heart.
• To identify regions of disturbed flow, recirculation, and stasis.
• To quantify velocities, turbulence, and shear stresses within the device.

Main Methods:

• Utilized dual camera video and synchronized still photography for flow pattern visualization.
• Employed diffused light and a planar laser source with tracer particles (magnesium oxide, Amberlite).
• Digitized flow trajectories to calculate velocities, turbulence, and shear stresses, synchronizing with pump motion.

Main Results:

• Identified disturbed, recirculating, and stagnation zones throughout the pumping cycle.
• Quantified global and local turbulence values.
• Observed simultaneous laminar and turbulent flow patterns, with velocities ranging from 2 to 145 cm/sec and shear stresses from 12 to 897 dynes/cm².

Conclusions:

• The study revealed complex flow dynamics, including simultaneous turbulence, stasis, and recirculation, within the artificial heart.
• These findings highlight areas for design improvement to minimize adverse flow conditions.
• Understanding these flow characteristics is vital for enhancing the hemocompatibility and efficacy of artificial heart technology.