Abstract: To analyze the influence of structural parameters on energy loss and hydraulic performance of water-ring vacuum pumps, this study combines numerical simulation with entropy generation theory to investigate the effects of different hub ratios and blade wrap angles on energy characteristics and operational performance. The results demonstrate that hydraulic losses primarily originate from turbulent dissipation entropy production and wall-effect entropy production, while direct dissipation entropy production contributes minimally. Significant turbulent kinetic energy and entropy production losses are observed in the impeller region, with high entropy generation rates predominantly distributed in the suction and discharge zones. Within the investigated ranges of hub ratio and blade wrap angle, wall entropy production losses exhibit a continuous increasing trend with both parameters. Peak suction capacity and efficiency are achieved at a hub ratio of 0.45, while optimal comprehensive performance occurs at a blade wrap angle of 13.5°. These findings provide theoretical guidance for performance optimization studies of water-ring vacuum pumps.