Abstract: The forms of lubrication medium include film, droplet and gas in an aeroengine bearing chamber, in which the wall film flow characteristics has the most important effect on the heat transfer characteristics of the wall .The oil film thickness and velocity were related to the droplet motion and deposition characteristics. The study of the droplet motion and deposition characteristics is the fundamental for lubrication design and heat analysis in an aeroengine bearing chamber. Based on the gas flow field in the bearing chamber, the Lagrangian method was used to establish analytical model of droplet motion. The numerical simulation of droplet motion was achieved by an instantaneous step method. The effects of droplet diameter and rotor speed on droplet velocity and trajectory were obtained. Based on the droplet motion state and droplet-wall impact model, the analysis of the effects of droplet diameter and rotor speed on droplet deposition efficiency and momentum transfer efficiency was achieved. The results indicated droplet diameter and rotor speed had great effect on droplet velocity, trajectory, deposition efficiency and momentum transfer efficiency, especially for the former. The analytical method in this paper had high reliability and precision by contrasting computational result with experimental result. The computation of droplet motion state, deposition efficiency and momentum transfer efficiency supplied initial condition to the computation of the oil film thickness, velocity, lubrication design and heat analysis of an aeroengine bearing chamber.

Key words: bearing chamber; droplet trajectory; two-phase flow; deposition efficiency; momentum transfer efficiency

Corresponding author: WANG Jun, Northwestern Polytechnical University, Xi’an 710072, China

E-mail: jswangjun@163.com

Tribology, Vol. 30, Issue 4, 2010, 361~366