航空发动机轴承腔通风结构嵌入改进及油气两相流动特性研究

Embedded Improvement of Ventilation Structure in Aircraft Engine Bearing Cavity and Study on Oil Gas Two Phase Flow Characteristics

为研究航空发动机轴承腔油气两相流动特性,提高轴承腔回油特性,针对轴承腔的通风结构提出嵌入改进方案;建立基于欧拉-欧拉方法轴承腔两相流求解模型,对不同工况下常规轴承腔和嵌入改进方案轴承腔流动特性和回油特性进行分析。研究结果表明,将常规轴承腔通风结构进行嵌入改进后,润滑油被嵌入的通风口壁面阻挡,在空气剪切力和重力的作用下,通风口右侧的润滑油掠过通风口向下游移动,从通风口流出的润滑油量减小,从回油口流出的润滑油增加,因而使得回油效率明显提升;随着嵌入深度的增加,从通风口流出的润滑油得到进一步抑制,腔内润滑油体积分数进一步增加,回油效率得到进一步提升;相比常规轴承腔,当润滑油流量为200 L/h,转速为15 000 r/min时,嵌入改进方案回油效率提升最为明显,嵌入深度为8、10、12 mm的改进方案回油效率分别提高了16.72%、18.80%和20.19%。

In order to study the oil-gas two-phase flow characteristics in the bearing chamber of an aeroengine and improve the oil return effect of lubricating oil,an embedded improvement scheme was proposed for the ventilation structure of the bearing chamber.A two-phase flow solution model for the bearing chamber based on the Euler-Euler method was established,and the flow characteristics and oil return characteristics of conventional bearing chamber and embedded improvement bearing chamber under different operating conditions were analyzed.The results show that after the embedded improvement of the ventilation structure of the conventional bearing chamber,the lubricating oil is blocked by the embedded ventilation wall.Under the action of air shear force and gravity,the lubricating oil on the right side of the ventilation port moves downstream through the ventilation port,reducing the amount of lubricating oil flowing out of the ventilation port and increasing the amount of lubricating oil flowing out of the return port,thus significantly improving the return oil efficiency.As the embedding depth increases,the lubricating oil flowing out of the vent is further suppressed,the volume fraction of the lubricating oil in the chamber further increases,and the return oil efficiency is further improved.Compared with conventional bearing cavities,when the oil flow rate is 200 L/h and the rotation speed is 15 000 r/min,the embedded improvement scheme has the most significant improvement in oil return efficiency,and the oil return efficiency is increased by 16.72%,18.80%,and 20.19% respectively for the improved schemes with embedded depths of 8 mm,10 mm,and 12 mm.