Investigation of the impact of trapezoidal suction surface impeller on internal flow and energy conversion in side channel pumps

This study investigates energy conversion enhancement in side channel pumps through trapezoidal suction surface impeller optimization. Analyses of impellers with varying suction angles demonstrate that θ = 45° trapezoidal scheme achieves superior hydraulic performance, exhibiting a 9.85 % head increase and 3.45 % efficiency improvement over conventional triangular impellers. Pressure and mass flow exchange analysis reveals accelerated formation of stable energy transfer regions and enhanced pressurization through amplified pressure pulsations effectively converted into hydraulic head. Vortex dynamics ( Ω -criterion) and entropy production evaluation confirm that the trapezoidal geometry suppresses high-intensity vortexes via streamlined separation at the suction surface's planar extension, reducing turbulent dissipation losses by 8.6 %. While expanded suction surface area marginally elevates wall entropy, this trade-off is outweighed by the dominant reduction in turbulent dissipation. The trapezoidal geometry fundamentally restructures energy conversion pathways by transforming chaotic vortex-driven dissipation into organized pressure work, establishing an efficiency-enhancing paradigm for ultra-low specific speed pumps. These findings provide mechanistic insights into optimizing energy transfer continuity in complex helical flow systems. • A novel 45° trapezoidal impeller increases pump head by 9.85 % and efficiency by 3.45 % at Q BEP compared to triangular designs. • Trapezoidal geometry effectively reorganizes chaotic flow structures, accelerating stable mass exchange formation, transforming vortex dissipation into organized pressure work. • Extended planar suction surface suppresses high-intensity vortexes by streamlined separation of high and low-speed flow regions indicated by the Ω-criterion analysis. • Turbulent dissipation losses decrease by 8.6 %, contributing to overall efficiency improvements, with the core loss reduction outweighing the minor wall entropy increase.