Numerical and Experimental Analysis for a Magnetic Levitation System in a Hemocompatibility Assessment Platform

Area of Science:

• Biomedical Engineering
• Medical Devices
• Hemodynamics

Background:

• Pediatric left ventricular assist device (LVAD) development faces challenges due to anatomical size and hemocompatibility constraints.
• Existing hemocompatibility assessment platforms (HAPs) can induce hemolysis, necessitating improved designs.
• Magnetic bearings are crucial for rotor suspension and axial positioning in advanced LVADs.

Purpose of the Study:

• To numerically evaluate the forces generated by active magnetic bearings (AMBs) for a hemocompatibility assessment platform.
• To validate numerical models of AMBs by comparing predictions with experimental data.
• To identify optimal operating parameters for AMBs to ensure rotor stability and minimize blood trauma.

Main Methods:

• Developed and numerically evaluated two geometries of active magnetic bearings (AMBs).
• Varied rotor-stator gaps (0.1-0.5 mm) and coil currents (-2 A to 2 A) to assess magnetic forces.
• Validated numerical models against experimental results to determine accuracy.

Main Results:

• Numerical models showed average errors of 8.8% and 7.0% for the two geometries.
• Higher model errors were observed at smaller rotor-stator gaps (<0.2 mm).
• Active magnetic bearings demonstrated high magnetic stiffness within a specific current range (-1 A to 1 A), indicating an optimal control region before saturation.

Conclusions:

• The validated numerical models provide a reliable method for evaluating AMB performance in HAPs.
• The identified optimal control region for AMBs is key for future algorithm development to stabilize rotors axially.
• This work advances the development of a hemocompatibility assessment platform, crucial for improving both adult and pediatric LVADs.