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Multi-Objective Optimization of the Impeller of a mini Blood Pump: Balancing Outlet Pressure and Scalar Shear Stress

Authors :

Reza Sahebi-Kuzeh kanan¹ Hanieh Niroomand-oscuii² Habib Badri Ghavifekr³ Farzan Ghalichi⁴

1- Tabriz University of Technology 2- Tabriz University of Technology 3- Tabriz University of Technology 4- Tabriz University of Technology

Keywords :

Blood pump،Computational fluid dynamics،Optimization،Response Surface Methodology،Multi-Objective Genetic Algorithm

Abstract :

Cardiovascular diseases are among the leading causes of mortality worldwide, and blood pumps and ventricular assist devices play a key role in advanced care. To overcome limitations of prior studies, namely the small number of geometric parameters and single objective optimization, we present a hybrid framework that integrates response surface methodology, a neural network surrogate, and a multi objective genetic algorithm to design the impeller of a small blood pump at a specified operating point. Fifteen geometric parameters were varied and 290 computational simulations were performed to construct the database and train the surrogate. The optimization objectives were to maximize outlet pressure and to keep the mean scalar shear stress at 50 Pa.Compared with the baseline impeller, the optimized design achieved a 6–7% increase in outlet pressure and about a 15% increase in static head, while the mean wall shear stress decreased by about 17% and the hemolysis index dropped by nearly 50%. The optimized blade reduced high-shear stress near the leading edge, yielded a more uniform shear field, and exhibited smoother pressure growth and weaker jet–wake structures, indicating more uniform blade loading, better pressure recovery, and lower mixing losses. The neural network correctly captured the improvement trends but showed a modest discrepancy: it overestimated outlet pressure by about 13% and underestimated the shear-stress reduction by about 19% relative to simulation-verified values. Overall, the proposed framework simultaneously improves hydraulic performance and hemocompatibility and offers a practical route for multi-objective optimization of small blood-pump impellers.