Computational fluid dynamics analysis of the pediatric tiny centrifugal blood pump (TinyPump)

Area of Science:

• Biomedical Engineering
• Fluid Dynamics
• Medical Devices

Background:

• Pediatric circulatory support requires specialized blood pumps.
• Hydrodynamic bearing design is critical for blood pump durability and hemocompatibility.
• Optimizing bearing clearance minimizes shear stress and hemolysis.

Purpose of the Study:

• To investigate the effect of hydrodynamic bearing clearance on shear stress and hemolysis in a pediatric blood pump.
• To optimize the bearing design for improved hemocompatibility and durability.
• To validate computational fluid dynamics (CFD) predictions with experimental hemolysis data.

Main Methods:

• Computational fluid dynamics (CFD) analysis to quantify secondary flow and wall shear stress.
• Evaluation of two bearing clearances (0.1 mm and 0.2 mm).
• Hemolysis testing to determine the normalized index of hemolysis.

Main Results:

• Reduced bearing clearance (0.1 mm) resulted in lower wall shear stress compared to 0.2 mm at 2 L/min and 3000 rpm.
• The axial component of shear rate decreased significantly with narrower clearance.
• Normalized index of hemolysis decreased to 0.0076 g/100 L with 0.1 mm clearance, aligning with CFD predictions.

Conclusions:

• CFD is a valuable tool for optimizing hydrodynamic bearing design in centrifugal blood pumps.
• Reducing bearing clearance to 0.1 mm improves hemocompatibility and reduces blood cell damage.
• Optimized bearing design enhances pump durability and antithrombogenic performance for pediatric applications.