Research on oil-gas and thermal characteristics of high-speed ball bearing after oil cutoff

Purpose Under high-speed conditions, oil cutoff severely compromises the heat dissipation capacity of bearings, which could trigger a rapid temperature rise and pose a critical challenge to their thermal endurance. This study integrates numerical simulations with experimental validation to investigate the transient thermal characteristics of bearings after oil cutoff. This study aims to provide a systematic framework for evaluating temperature performance under high-speed, oil cutoff conditions. Design/methodology/approach A quasi-static method combined with localized friction modeling is used to calculate frictional heat generation, while the volume-of-fluid method is adopted to accurately capture the oil–gas two-phase flow dynamics within the bearing cavity. The study systematically examines the effects of varying rotational speeds on oil distribution and thermal evolution. Findings After oil cutoff, the oil volume fraction within the bearing cavity rapidly decreases to a steady state, concurrently accompanied by a sharp decline and stabilization of the convective heat transfer coefficient on the cavity wall surface. At a rotational speed of 35,000 rpm, the peak temperature of the inner ring for the bearing reaches 245.46°C after 30 s of oil cutoff. This means that there is a 51% increase compared to steady oil supply conditions. In contrast, the outer ring exhibits a lower peak temperature of 144.88°C, which reflects a 34% increase. Originality/value This study proposes a validated computational method capable of efficiently analyzing internal temperature distributions of bearings, which can provide a practical and reliable alternative for extreme performance design in high-speed bearing systems. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-09-2025-0446/