Numberical Simulation Of Two-phase Flow In Aero-engine Bearing Chamber

Bearing chamber as the interface between the oil and the secondary air flow is one of themost important components in aero-engine lubrication system. The two-phase flowcharacteristic of air/oil mixture in bearing chamber affects the operational stability ofaero-engines. Particular study of the two-phase flow inside the aero-engine rolling bearingplays a vital role for bearing lubrication, cooling and the design of bearing chamber in thelubrication system. The film distribution and movement in oil and air interface have beenshowed.The two-phase flow state is formed when the lubricant oil is ejected into the highpressure compressor rear bearing cavity. The complex two-phase flow simulation model isbuilt based on the volume of fluid (VOF) method, RNG k–ε turbulence method and slidingmesh technique in this paper. The influence of the different operating parameters on pressure,velocity and oil volume fraction are presented respectively. The relationships of the revolutionspeed and lubrication flow rate with the oil volume fraction were set up.The heat source and the amount of generation of the rolling bearing are analyzed andcalculated in the condition of different rotational speeds. The research of temperature fieldinside the rolling bearing is simulated by CFD approach. The operating temperatures ofbearing are obtained under different operating conditions. The temperature changes in bearinginner and outer rings have been analyzed. The influence of oil feeding rate on the lubricationeffect are carried out in the simulation, which show that the feeding rate is a very importantparameter for the oil lubrication system and an optimum oil feeding rate exists at differentworking condition. Under the optimum feeding rate the rolling bearing will have lowesttemperature rising speed, and more than or less than this oil feeding rate will make thetemperature rising speed higher.