Lubrication Analysis Of Oil-air Two Phase Flow In High Speed Precision Angular Contact Ball Bearings

Along with the constantly raise of rotational speed of principal axis,the lubrication and cooling problems for the high speed precision angular contact ball bearings gradually become the key factor for limit spindle speed increase. Due to the limitation of its own conditions,the use of grease lubrication or oil mist lubrication,is imbalanced with the constantly raise of rotational speed of principal axis. So it needs improvement the existing lubrication and cooling technology. Currently,oil-air two-phase lubrication is adopted as the recommended lubrication and cooling technology for the bearings. And this paper is based on a university-enterprise cooperation projects with a domestic bearings manufacturers and referenced to the principle of oil-air two-phase annular flow lubrication. A study for horizontal pipe and the bearings chamber is implemented to do some research about lubrication. This paper concentrates on:1. In order to study the formation mechanism and its extend of the oil-air two-phase flow in a horizontal pipe,an oil-air pipeline model which is horizontal has established. Using the RNG k-? turbulence model and VOF model of FLUENT,according to different oil input has carried on the simulation analysis. Simulation results show that with air supply velocity under the condition of constant to 30m/s, in order to form a stable oil-air two-phase annular flow in the pipe,the best oil delivery rate is about 1 m/s.2. In order to study the distribution of flow field in the bearings chamber,the 7014 angular contact ball bearings fluid domain model has established. Using the RNG k-? turbulence model、VOF model and Sliding Mesh model of FLUENT. Under two kinds of conditions,one is the same lubrication parameters and different rotational speed of principal axis. Another is the same rotational speed of principal axis and different lubrication parameters. To analysis the distribution of flow field in the bearings chamber,entrance velocity analysis,distribution of oil in the chamber,path lines map,oil phase volume fraction contrast, temperature contrast and pressure contrast have been researched. Simulation results show that as to the distribution of oil in the chamber,it shows that oil phase volume fraction from the lubrication area, after lubrication area, before lubrication area reduce in turn;temperature in bearings chamber is largely affected by much affected by rotational speed of principal axis,The higher rotational speed of principal axis is, the higher temperature in the chamber it has.