Numerical Analyses for Low Reynolds Flow in a Ventricular Assist Device

Area of Science:

• Biomedical Engineering
• Fluid Dynamics
• Computational Science

Background:

• Blood pump development is crucial for cardiac patient treatment and quality of life.
• Numerical tools are essential for optimizing the design of ventricular assist devices (VADs).
• Turbulence development at low impeller Reynolds numbers in VADs lacks consensus.

Purpose of the Study:

• To analyze flow behavior in VADs at low impeller Reynolds numbers.
• To compare different computational fluid dynamics (CFD) turbulence models for VAD simulations.
• To provide recommendations for suitable turbulence models for low Reynolds number VAD analyses.

Main Methods:

• Computational numerical simulations were performed under various scenarios at a constant rotation speed.
• Two modeling approaches were used: laminar flow and multiple turbulent flow models (κ-ε, κ-ω, Spalart-Allmaras).
• Simulations focused on impeller Reynolds numbers around 2800, relevant to VADs and stirred tanks.

Main Results:

• Simulation results align with existing literature for VADs and transient flows in stirred tanks.
• A comparison of turbulent models was conducted.
• The study identified specific turbulent models suitable for low impeller Reynolds number analyses in VADs.

Conclusions:

• The study validates CFD simulations for VADs at low Reynolds numbers.
• Turbulence models such as κ-ε RNG, standard and SST κ-ω, and Spalart-Allmaras are recommended for VAD numerical analysis.
• Accurate modeling of flow behavior is key to improving VAD design and patient outcomes.