关键词: 壁面油膜, 航空发动机, 均匀流体, 油气两相, 轴承腔

Abstract: The accurate lubrication and heat transfer designs of an aeroengine bearing chamber require an understanding of the complex air/oil two-phase flow characteristics in the chamber. A homogeneous fluid/wall oil film two-phase stratified flow model is proposed to investigate the air/oil two-phase lubrication medium flow in an aeroengine bearing chamber, and the effects of shaft speed and oil mass flow rate on the pressure, flow velocity and temperature for the homogeneous fluid and wall oil film are discussed in detail. In the model, the equivalent physical feature parameters of air (containing droplets) are determined by the component rate of droplets and air in the mixture of air and droplets, and the convection heat transfer coefficients between relevant walls and fluid medium in the bearing chamber are calculated by their convection heat transfer characteristics, respectively. The calculation results show preliminarily that the pressures of the homogenous fluid and wall oil film increase with increasing oil mass flow rate, and are influenced complexly by shaft speed; that the flow velocities of the homogenous fluid and wall oil film increase with increasing shaft speed, and are influenced insignificantly by oil mass flow rate; that the homogenous fluid temperature decreases with increasing oil mass flow rate, and are influenced slightly by shaft speed; and that the wall oil film temperature increases with increasing shaft speed and decreasing oil mass flow rate. Finally, a bearing chamber experimental facility is built, and the pressure and temperature under the air/oil two-phase flow condition are measured in the bearing chamber. The calculation results agree well with experimental data.

Key words: aeroengine, air/oil two-phase, bearing chamber, homogeneous fluid, wall oil film