CFD-based analysis of load-independent power losses in high-speed cylindrical roller bearing considering internal geometry effects

Predicting load-independent power losses in cylindrical roller bearings (CRBs) under high-speed operating conditions is essential for enhancing system efficiency. However, traditional empirical models often fail to account for the influence of internal geometry of bearings. This study investigates the effects of rotational speed and variations in internal geometry on load-independent power losses in bearings using computational fluid dynamics (CFD). A single phase model using an equivalent-fluid approach and the moving reference frame (MRF) method was applied to investigate internal flows of bearings. The results showed that load-independent power losses increase non-linearly with speed, from 0.030 kW at 10,000 rpm to 0.709 kW at 30,000 rpm. Comparative analysis showed that while CFD results were consistent with the ISO/TR 14179–1 trends, the results diverged significantly from the SKF model at high speed. Furthermore, internal geometry variations significantly affected load-independent power losses. The N-type bearing exhibited the highest losses (40.4% higher than the NU type) due to rib-induced shear stress concentration, whereas cage #3 minimized losses (10.9% lower than cage #2) by reducing the pressure acting on the cage bridges. This method can be utilized for predicting load-independent power losses, providing insights for optimizing high-speed CRB designs.