Abstract: As regards to the relationship between overheat and fire and two phase gas/oil bubble flow in aero-engine bearing chamber, the characteristics of this flow are necessary to be studied by numerical calculation, which can provide reference to the design of lubrication of bearing chamber. For the one type of aero-engine bearing chamber, the bubble flow mathematical model is built and the flow characteristics can be further studied with this model. During building the model, N-S equations, coalescence and break-up factors are introduced for considering bubble diameters and breakup and coalescence effect. Based on two-body fluid model and turbulent model, the two-phase bubble flow in bearing chamber is established and solved by the finite difference method in three-dimension. As a result, the flow area is simulated. And the experimental data from foreign reference paper validate the theoretical analysis. The results show that the distribution of bubble in bearing chamber is relevant to shaft speed. It is also investigated how air/oil mixture speed and pressure at outlet is affected by physical parameters, such as void fraction, and condition parameters, such as rotor speed and air/oil mixture inlet speed. Finally, the proposed analysis is verified by the experimental data, which proves the theoretical method is feasible and reliable for the design of bearing chamber in aero-engine.

Key words: Air/oil two-phase flow, Bearing chamber, Bubble flow, Population balance equations