Analysis of oil capture characteristics and global sensitivity of radial oil scoops with different blade radius differences for high-speed bearings

Abstract

Aero-engines that employ under-race lubrication technology offer significant advantages by ensuring adequate lubrication and cooling of the bearings, while also achieving substantial weight reduction and size optimization. The oil capture characteristics, including oil capture efficiency and captured oil amount, in radial under-race lubrication are influenced by the operating and structural parameters of the oil scoop. This study presents a comprehensive investigation of radial oil scoops with varying blade radius differences, combining numerical simulations and experimental investigations. The findings indicate that appropriately reducing the blade radius difference enhances the maximum oil capture efficiency while simultaneously raising the corresponding threshold speed. Among the tested configurations, the design with a 7.5mm radius difference demonstrates the highest oil capture efficiency under most operational conditions. Furthermore, a surrogate model integrated with global sensitivity analysis quantitatively assesses the influence of design parameters on oil capture characteristics, highlighting the injection angle as the most significant factor. Finally, by fitting data on the momentum flux ratio and optimal injection angle, a predictive correlation between these variables is established, with a maximum error of merely within 4%. This comprehensive research contributes to the advancement of radial under-race lubrication systems in aero-engines, leading to optimized designs that enhance overall performance and efficiency.