Volumetric efficiency analysis of microsegment gear pumps considering cavitation: Modeling and experiments

To address the issue of large volumetric efficiency calculation error and neglect of cavitation effect in current gear pump research, this paper proposes a method combining theoretical and fluid analysis for accurate calculation of gear pump volumetric efficiency, providing guidance for gear pump development. Taking the microsegment gear pump (MSGP) as an example, a leakage model is established based on the flat-plate laminar flow principle and the Navier-Stokes equation. The impact of cavitation on volumetric efficiency is analyzed, and based on the proposed non-equilibrium cavitation model by authors, the effect of cavitation on gear pump oil viscosity is examined. On the basis of the above models, a comprehensive volumetric efficiency model of the MSGPs considering cavitation is established and validated through fluid analysis and experiments, with the error from experimental data within 2%. In addition, the total gas volume fraction in the pump and the volumetric efficiency follow the same trend, but in the opposite direction.