Disintegration of Oil Jets Emerging From Axial Passages at the Face of a Rotating Cylinder

A fundamental study has been performed to examine the disintegration of oil films emerging from axial passages at the face of a rotating cylinder. The investigation has been conducted in parallel to a similar study on atomization processes at rotating radial holes (Glahn, A. et al., 2001, Disintegration of Oil Films Emerging From Radial Holes Inside a Cylinder, ASME Paper No. 2001-GT-0202) and has used the same approaches in simulating one of the droplet generation sources in aeroengine lubrication systems. Both papers aim to contribute to the establishment of a database that can be used for the development of droplet generation models directly applicable to engine conditions. As with the parallel investigation, the near-term objectives of fundamental oil film disintegration studies are (i) to determine droplet sizes under relevant aeroengine bearing compartment operating conditions, and (ii) to measure individual droplet diameter/velocity relationships. The long-term objective is to incorporate this information into advanced design systems such as CFD-based tools. In the present study, flow visualization has been used to identify the dominant disintegration processes. Droplet diameters and velocities have been obtained for relevant engine operating conditions. Data are presented in terms of both characteristic diameters and size-class resolved droplet velocities and flow angles. A comparison of droplet sprays measured in the present study with those generated by disintegration of oil films at the rim of a rotating disk (Glahn, A. et al., 2000, Droplet Generation by Disintegration of Oil Films at the Rim of a Rotating Disk, ASME Paper No. 2000-GT-0279) has been enabled by introducing nondimensional parameters for atomization products and operating conditions.