Session: 23-03 Oil & Rolling Element Bearings

Paper Number: 152538

Investigation of Air Flow in Turbomachinery Bearings Using a Computational Fluid Dynamics Approach 

A CFD model was created in the commercially available ANSYS Fluent software. It simulates a geometric configuration of a class of bearings which is ubiquitous in the field of turbomachinery and is based on actual flight hardware. This model is transient and fully three dimensional. Additionally, it accounts for motion of the geometric configuration based on a detailed kinematic analysis, which includes the definition of contact angle of the bearing and the resulting misalignment of the rolling elements’ rotational axes with the rotation axis of the shaft. This misalignment leads to a natural pumping action of the bearing, and the resulting air flow is modeled using Unsteady Reynolds-Averaged Navier Stokes (URANS) based k-ω SST turbulence model.

Different combinations of the inflow boundary conditions were simulated in this study. The results indicate that the natural pumping action of the bearing is significantly affected by the upstream conditions. They further show that the tangential component of the velocity is predominant for the flow inside the bearing, and it is one order of magnitude more than the other two components. Finally, it is observed that bearings without a protruding shaft aspirate 3.6 times more air, by volume, than bearings with a protruding shaft.

Presenting Author: Sampath Rachakonda Zulu Pods Inc.

Presenting Author Biography: Dr Rachakonda is a Thermal Fluid Analyst with Zulu Pods Inc. He has a PhD in Mechanical Engineering from the University of Massachusetts Amherst, with an extensive background in the computational modeling of multiphase flows and combustion systems. He was previously associated with GE Research and Argonne National Laboratories.

Authors:

Sampath Rachakonda Zulu Pods Inc.
Marios Soteriou Zulu Pods Inc.
Adam Smedresman Zulu Pods Inc.
Todd Currier Zulu Pods Inc.