The Effects of Impeller Blade Count on Centrifugal Pump Performance and Efficiency Under Different Operating Conditions: A Comparison of Numerical Prediction

Abstract

Centrifugal pumps are widely used across various industries, such as water delivery, chemical processing, and HVAC systems, due to their efficiency and reliability in fluid handling. However, optimizing their performance remains a critical challenge, particularly in balancing head and efficiency under different operating conditions. This study explores the effect of impeller blade count on the performance and efficiency of centrifugal pumps using ANSYS 2024R1 computational fluid dynamics (CFD) simulations and polynomial regression models. Pumps with four, five, six, and seven blades were examined across flow rates (100–400 m³/h) and rotational speeds (1,500–4,500 rpm) to identify an optimal balance between performance and efficiency. The results reveal that increasing the blade count enhances fluid handling by reducing pressure fluctuations and creating more uniform pressure and velocity distributions. Among the configurations, the five-blade impeller at 2,500 rpm exhibited the best performance, achieving a head of 28.10 m and an efficiency of 91.9%. At higher speeds, efficiency peaked at specific blade counts but declined due to increased hydraulic losses. The seven-blade impeller produced the highest head of 64.1 m at 4,500 rpm, though efficiency dropped to 79.5%, highlighting the trade-off between head and efficiency. The regression models demonstrated high accuracy for each blade count. Notably, the four-blade configuration provided the most reliable predictions, with R² values of 0.9998 for the head and 0.9442 for efficiency. Similarly, the five-blade model showed strong performance, achieving R² values of 0.9972 for head and 0.7785 for efficiency. This study underscores the importance of selecting the optimal impeller blade count to balance performance and efficiency. Future work should investigate the influence of additional design parameters, such as blade angle and material composition, to further enhance centrifugal pump performance.

Introduction

Centrifugal pumps are essential across industries for fluid transport due to their efficiency and reliability. However, optimizing performance, particularly balancing head and efficiency under varying conditions, remains challenging. This study investigates the effect of impeller blade count on pump performance using ANSYS 2024R1 CFD simulations and polynomial regression models.

Pumps with 4 to 7 blades were analyzed across different flow rates (100–400 m³/h) and rotational speeds (1,500–4,500 rpm). Results showed:

• Increasing blade count improves pressure stability and flow uniformity.

• The five-blade impeller at 2,500 rpm had the best performance, achieving a head of 28.1 m and efficiency of 91.9%.

• The seven-blade impeller produced the highest head (64.1 m) at 4,500 rpm but with lower efficiency (79.5%) due to hydraulic losses.

• Regression models accurately predicted performance, especially for the four-blade design (R² = 0.9998 for head; 0.9442 for efficiency).

The study confirms that blade count significantly influences pump efficiency and head. It recommends optimizing blade count based on operating conditions and suggests future work on parameters like blade angle and material.

Conclusion

This study analyzed the influence of impeller blade count on centrifugal pump performance using ANSYS 2024R1 CFD simulations and polynomial regression models. The findings reveal that the five-blade configuration at 2,500 rpm delivered the best performance, achieving a head of 28.10 meters and an efficiency of 91.9%. This balance highlights the configuration\'s suitability for efficient and stable fluid handling. Increasing the blade count improved pressure and velocity distribution, reducing pressure fluctuations and enhancing fluid dynamics. However, this improvement reached diminishing returns beyond five blades, as higher blade counts increased hydraulic losses due to friction and turbulence. At 4,500 rpm, the seven-blade configuration achieved the highest head of 64.1 meters but with reduced efficiency at 79.5%, demonstrating a clear trade-off between head and efficiency at higher rotational speeds. The regression models demonstrated high accuracy in predicting pump performance. Notably, the four-blade configuration provided the most reliable predictions, with R² values of 0.9998 for the head and 0.9442 for efficiency. Similarly, the five-blade model showed strong performance, achieving R² values of 0.9972 for head and 0.7785 for efficiency. Efficiency generally peaked with a five-blade count before declining at seven blades due to hydraulic losses. Flow rates significantly influenced head and efficiency, with lower flow favouring higher efficiency. Experimental validation, advanced turbulence models

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Copyright

Copyright © 2025 Enemugha Emmanuel Ebikabowei, Mohd Sayuti Bin Ab Karim, Nik Nazri Bin Nik Ghazali. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.