Temperature Rise Characteristics of Fluid-Solid Coupling in Grease-Lubricated Tapered Roller Bearings for Wind Turbine Gearboxes

 Background

Tapered roller bearings in wind turbine gearboxes are critical components of the drivetrain system, and their operational reliability directly affects the service life of both the gearbox and the entire wind turbine. Due to the compact structure of the gearbox, these bearings are prone to temperature rise under complex external operating conditions and harsh environments, which can lead to lubrication failure. Grease lubrication, as one of the primary lubrication methods for gearbox bearings, exhibits unique rheological properties that result in complex flow distribution within the bearing cavity, significantly influencing both lubrication performance and heat dissipation. Therefore, analyzing the fluid-solid coupling temperature rise characteristics based on the rheological properties of grease is of great importance for improving bearing operational conditions, enhancing lubrication performance, and extending service life.

Abstract

To enhance the operational performance of grease-lubricated tapered roller bearings in wind turbine gearboxes, this study investigates their fluid-solid coupling temperature rise characteristics. Using a rotational rheometer, the relationship between shear stress, viscosity, and shear rate of Mobil SHC 460WT grease was measured at different temperatures. The Herschel-Bulkley non-Newtonian model was applied to fit the rheological parameters at varying temperatures. A fluid-solid coupling temperature rise model of tapered roller bearings was established in Fluent software to analyze temperature variations under different grease filling levels, rotational speeds, loads, and ambient temperatures. The simulation results were validated using a wind turbine bearing test rig. The results indicate that the overall temperature of the bearing exhibits a gradient distribution, with heat generated in the roller-raceway contact region diffusing outward. The average temperature of the rollers is the highest, followed by the inner ring, while the outer ring exhibits the lowest temperature. Increasing the grease filling amount improves heat transfer efficiency within the fluid domain, resulting in decreased temperatures of the rollers and inner ring and increased temperature of the outer ring. Both higher rotational speed and increased load raise the bearing frictional power consumption, leading to a higher steady-state temperature.

Conclusions

Based on Fluent simulations and corresponding temperature rise tests of tapered roller bearings in wind turbine gearboxes, the following conclusions were drawn:

The overall bearing temperature exhibits a gradient distribution, with heat generated in the roller-raceway contact region diffusing outward. The average roller temperature is the highest, followed by the inner ring, and the outer ring is the lowest.

Increasing the grease filling amount improves heat transfer within the fluid domain, reducing the temperatures of the rollers and inner ring while increasing the outer ring temperature. Higher rotational speeds and loads increase frictional power consumption, resulting in higher steady-state bearing temperatures. Additionally, an increase in ambient temperature leads to a uniform rise in the average temperatures of all bearing components.

Under 80% load, temperature rise test results at different rotational speeds closely match the simulation results, with consistent trends. The maximum deviation occurs at 45 r/min, where the simulation differs from the experimental result by 8.11%, confirming the accuracy of the simulation model.

Reference:

Temperature rise characteristics of fluid-solid coupling in grease-lubricated tapered roller bearings for wind turbine gearboxes, 2026(4):45-53.