Investigation on two-phase flow characteristics and oil capture performance of axial oil scoop in aero-engine

Abstract

Due to the improvement in the performance of aero-engines and the continuous size reduction, efficient under-race lubrication is becoming more and more important to provide the proper amount of lubricant oil for the main shaft rolling bearings. In this paper, experimental tests and numerical simulations are conducted to investigate the two-phase flow behavior and oil capture performance of the axial oil scoop. It is found that the oil capture efficiency increases with the decrease of injection distance, while the maximum increment of oil capture efficiency is less than 1.5% within the range of 58 mm–128 mm. The measurement results show that the oil capture efficiency first rises to the maximum value of 100% with increasing rotational speed, and then keeps the maximum value constant. Adjusting the oil supply pressure difference can reduce the oil loss and improve the oil capture performance. The oil capture efficiency decreases with increasing jet angle, and the oil capture efficiency corresponding to jet angle of 15° decreases by more than 20% at the rotational speed of 15000r/min. The experimental results are used to develop a corrected discharge coefficient formula based on the rotation coefficient. The predicted results from this formula have a maximum relative error of less than 6%.

Keywords

• Under-race lubrication
• Axial oil scoop
• Two-phase flow
• Oil capture efficiency
• Captured oil mass flow rate