Effect of vane tip clearance on cavitation and gas–liquid two-phase flow characteristics of high-speed rotary vane pump

As core components of eroengine lubricating oil systems, the reliability of lubricating oil pumps is crucial for maintaining oil circulation and ensuring engine operational integrity. Rotary vane pumps (RVPs) are highly efficient, stable, and compact, making them suitable for eroengine lubricating oil systems. However, they suffer from performance degradation under prolonged high-speed operation, owing to vane tip wear and clearance expansion. This study numerically investigates the effects of vane tip clearance on cavitation and gas–liquid two-phase flow in a high-speed RVP. The RNG k-ε turbulence model, Singhal full cavitation model, and volume-of-fluid (VOF) multiphase flow model are employed. The results indicate that under single-phase oil inlet conditions, increased vane tip clearance has a minimal influence on cavitation in the pump chamber, but reduces outlet flow pulsation amplitude and volumetric efficiency. Pressure fluctuations at the pump outlet remain relatively stable, with the dominant pulsation frequency being equal to the rotational frequency. Under two-phase oil–gas conditions, increased vane tip clearance leads to decreased instantaneous flow fluctuation, induces uneven oil–gas phase distribution in the pump chamber, lowers the maximum outlet pressure, and increases leakage. Spectral analysis reveals that the dominant frequency of pressure pulsations corresponds to the shaft rotation and that the secondary frequency is the vane frequency. To optimize performance and reduce leakage, it is recommended to maintain a vane tip clearance of 0.035 mm and avoid operating the pump under high-gas-content conditions. These results provide theoretical guidance for designing and selecting RVPs, with significant implications for the further development of eroengine lubricating oil systems.