Optimizing hollow fiber membrane oxygenators: A multi-objective approach for improved gas exchange and reduced blood damage

Extracorporeal Membrane Oxygenation provides life-saving support for patients with severe heart and lung dysfunction; however, its implementation is associated with significant complications, including hemolysis and thrombosis. These complications address the need for an improved design of hollow fiber membrane oxygenators. This study presents a multi-objective optimization framework aiming to enhance the gas exchange efficiency while minimizing blood damage. A 2D computational fluid dynamics model, validated with micro-PIV measurements, was developed to simulate 200 fiber configurations defined by three geometric parameters (fiber diameter, distance-to-diameter ratio, and angle) and a flow parameter (blood flow rate). Specific CO₂ removal, dead-zone-to-total-area ratio, and hemolysis index were established as objectives, representing gas exchange efficiency, thrombosis potential within the membrane module, and hemolysis, respectively. Objectives were modeled using multivariate polynomial functions with unknown exponents and determined using the modified enhanced Jaya algorithm. Single-objective and multi-objective optimization were performed using Pareto front solutions, followed by weighted sum and goal programming methods to identify optimal arrangements. The findings demonstrated that the maximum obtained specific CO₂ removal, dead-zone-to-total-area ratio, and hemolysis index are 250.3 mL_CO2 min^-1 m^-2, 0.0254 %, and 0.011 $\times$ 10⁻³ %, respectively. Furthermore, this study identifies the distance-to-diameter ratio as the key factor affecting all the objectives. Finally, the calculated optimal configuration from both weighted sum and goal programming methods suggests that the best configuration includes low angle, small diameter, and relatively moderate distance-to-diameter ratio, and high blood flow rate.