Numerical Simulation of Lubricant Film Dynamics in Ball Bearings



This is a BMBF project in cooperation with Rockwell Collins Deutschland GmbH.

Modern ball bearings used in space applications have to fulfill high requirements in extreme situations (high rotational speeds and pressure), especially with respect to durability and lubricant consumption. A basic understanding of the dynamic processes involved such as lubricant transport, film thickness, pressure distribution and thermal effects is of high importance for future developments.

This application poses a variety of numerical challenges, such as anisotropy and extreme values of pressure. The lubricant is governed by the Navier-Stokes equations and a generalized Newtonian model. To simulate oil transport and oil consumption, we have to include the evolution of the free surface of the lubricant. Due to rotational speeds of up to 6000 rounds per minute, we observe locally very high pressure values leading to deformations in ball and race. It is essential to consider these coupling effect between lubricant and structure into the numerical simulations.

The goal of this project is a robust and reliable simulation of these dynamic processes up to high rotational speeds.



Sketch of the geometry



Simulation of the evolution of the lubricant's free surface