Investigation of oil flow in a ball bearing using Bubble Image Velocimetry and CFD modeling

The objectives of this investigation were to experimentally and analytically study the oil flow inside an angular contact ball bearing using Bubble Image Velocimetry (BIV). A counter-rotating angular contact ball bearing test rig (CRACTR) was designed and developed such that both bearing races can be rotated simultaneously in opposite directions, allowing for detailed observation of a single cage pocket in a stationary reference frame. Transparent acrylic cages were developed based on the original geometry of the cage and installed in the bearing. The oil flow inside the cage and bearing were analyzed using a high-speed camera. BIV was used to track bubbles in the oil and to understand the flow pattern inside the bearing. Ansys Fluent software was used to develop a computational fluid dynamics (CFD) model for the bearing. Results from the analytical model corroborate well with the experimentally observed oil flow streamlines and demonstrate the influence of operating conditions and cage designs on fluid flow. The CFD model provided details such as oil velocity at different locations in the bearing and fluid drag torque. The quantitative and qualitative validation of CFD results provides a basis for cage design for efficient lubricant flow inside a bearing.