Predicting centrifugally-driven lubricant outflow from porous bearing cages

TY - JOUR

T1 - Predicting centrifugally-driven lubricant outflow from porous bearing cages

AU - Feng, Xiangyu

AU - Zhu, Pengzhe

AU - Wang, Wenzhong

N1 - Publisher Copyright: © 2026 Elsevier Ltd

PY - 2026/2/1

Y1 - 2026/2/1

N2 - Aerospace bearings in spacecraft mechanisms require decades of autonomous operation under extreme conditions, making precise control of lubricant release from porous bearing cages essential. However, predicting this release behavior remains a significant challenge. This study develops a two-scale predictive framework derived from Navier-Stokes equations for centrifugally-driven lubricant outflow, encompassing both pore-scale and macroscale criteria. A characteristic parameter for quantifying the lubricant outflow state within porous cages was developed, which is governed by seven controlling parameters: pore size, rotation speed, rotation radius, lubricant density, surface tension, characteristic contact angle, and characteristic channel length. Validation through finite element simulations, centrifugal experiments, and literature data demonstrates strong agreement between predictions and observations. The resulting phase diagrams provide systematic design guidance for aerospace bearing cages, enabling the determination of outflow speeds and optimization of pore structures for specific operational requirements. This physics-based approach establishes the theoretical foundation and practical tools essential for next-generation aerospace bearing systems.

AB - Aerospace bearings in spacecraft mechanisms require decades of autonomous operation under extreme conditions, making precise control of lubricant release from porous bearing cages essential. However, predicting this release behavior remains a significant challenge. This study develops a two-scale predictive framework derived from Navier-Stokes equations for centrifugally-driven lubricant outflow, encompassing both pore-scale and macroscale criteria. A characteristic parameter for quantifying the lubricant outflow state within porous cages was developed, which is governed by seven controlling parameters: pore size, rotation speed, rotation radius, lubricant density, surface tension, characteristic contact angle, and characteristic channel length. Validation through finite element simulations, centrifugal experiments, and literature data demonstrates strong agreement between predictions and observations. The resulting phase diagrams provide systematic design guidance for aerospace bearing cages, enabling the determination of outflow speeds and optimization of pore structures for specific operational requirements. This physics-based approach establishes the theoretical foundation and practical tools essential for next-generation aerospace bearing systems.

KW - Bearing cages

KW - Centrifugal effect

KW - Lubricant outflow state

KW - Lubrication systems

KW - Porous materials

KW - Tribology

UR - https://www.scopus.com/pages/publications/105026659443

U2 - 10.1016/j.ijmecsci.2026.111184

DO - 10.1016/j.ijmecsci.2026.111184

M3 - Article

AN - SCOPUS:105026659443

SN - 0020-7403

VL - 311

JO - International Journal of Mechanical Sciences

JF - International Journal of Mechanical Sciences

M1 - 111184

ER -