Blade number effects on performance and internal flow dynamics in high-speed coolant pumps
Dongcheng Wang, Yandong Gu, Christopher Stephen, Qingfeng Ji
Abstract
The high-speed coolant pump is a critical component in battery energy storage systems, responsible for circulating heat transfer fluid and enabling efficient thermal energy exchange. This study investigates the effect of blade number (Z = 4–9) on the pump's energy performance and internal flow characteristics through experimental and numerical methods. Results show that as the blade number increases, the head and efficiency initially rise and then decline, with Z = 6, Z = 7, and Z = 8 achieving comparable performance at 1.0Qd. While changes in blade number minimally affect disk, volumetric, and volute efficiencies, they significantly influence hydraulic and impeller efficiencies. Pressure distribution analysis reveals that increasing the blade number to Z = 6 and Z = 7 reduces the low-pressure region at the impeller inlet and improves uniformity. Flow characteristics analysis shows that increasing the blade number reduces flow separation and the “jet-wake” effect but an excessive number of blades also raises turbulent kinetic energy, compromising flow stability. Similarly, entropy production decreases initially but rises again at Z = 8 and Z = 9, resulting in reduced energy performance. Overall, the pump's energy performance and internal flow characteristics follow an “inverted U-shaped” trend as blade number increases, highlighting the importance of selecting an appropriate blade number to improve flow conditions, minimize energy losses, and enhance operational stability. This study provides valuable insights for optimizing blade design in coolant pumps.