Two-Sided Feed Analysis in Gerotor Pumps to Enhance Filling Performance Through Computational Fluid Dynamics

Abstract In the context of CO2 emissions reduction, internal combustion engines are being replaced by electric motors in many applications. In hydraulic fluid power, this transition requires gear pumps to operate at much higher speeds than traditional systems, increasing the risk of incomplete chamber filling. This issue leads to significantly increased noise levels. Supplying the variable-volume chambers from both sides of the rotor is a well-known method for improving filling. This study investigates various inlet port placements for dual-sided feeding using a validated computational fluid dynamics (CFD) model of a gerotor pump. Two axial inlet positions, aligned with the shaft, and three radial positions are investigated. In addition, the axial-flow configuration is evaluated under varying inlet duct angles, while a slide is implemented in the radial configuration to assess its effect on flow direction. For radial feeding, the axial alignment of rotors relative to the housing space is evaluated, comparing symmetric and asymmetric configurations. Results indicate that axial feeding outperforms radial feeding, with optimal performance achieved when the duct is aligned with the variable-volume chambers. For radial feeding, a perfectly symmetrical configuration is preferable, though slightly asymmetrical setups yield comparable performance. Conversely, highly asymmetrical designs, while superior to single-side feeding, fail to fully exploit the advantages of dual-side feeding. This research demonstrates that, under high-speed operating conditions, CFD-based optimization of the suction volume can significantly improve volumetric efficiency by several percentage points.