航空发动机轴承腔油气两相流动特性及改进研究

Oil-Gas Two-Phase Flow Characteristics and Improvement of Bearing Chamber for an Aeroengine

关键词:  航空发动机  油气两相流  轴承腔  通风结构  回油结构  回油效率

Key words:  Aeroengine  Oil-gas two-phase flow  Bearing chamber  Vent structure  Scavenge structure  Return-oil efficiency

摘要:

为了研究航空发动机轴承腔油气两相流动特性，改善滑油回油效果，建立了基于欧拉-欧拉方法轴承腔两相流求解模型，针对轴承腔的通风结构和回油结构提出了三种改进方案，对不同工况下常规轴承腔和三种改进方案流动特性和回油特性进行深入分析。研究结果表明，将常规轴承腔通风结构进行嵌入（Embed）改进后，滑油被嵌入的通风口壁面阻挡，从通风口流出的滑油量减小，回油效率明显提升；将常规轴承腔回油结构进行斜坡（Slope）改进后，回油口右侧滑油堆积区消失，腔内滑油体积分数减小，回油效率明显提升；组合改进方案（ES）能够兼顾嵌入和斜坡改进方案的优势，回油效率进一步提升。相比常规轴承腔，当滑油流量为200L/h，转速为15000r/min时，嵌入、斜坡和组合改进方案回油效率分别提高了16.47%，13.02%和32.81%。

Abstract:

In order to study characteristics of oil-gas two-phase flow in bearing chamber of an aero-engine and improve return effect of oil， an unsteady two-phase flow solution model of the bearing chamber was established based on Euler-Euler method， and three improvement schemes were proposed for vent structure and scavenge structure of the bearing chamber. The oil-gas two-phase flow field characteristics and return-oil characteristics of a conventional bearing chamber and three improvement schemes under different working conditions were further analyzed. The results show that for the improved bearing chamber with embedded vent， oil was blocked by wall surface of the embedded vent， the oil flow from the vent decreased， and return-oil efficiency increased obviously. For the improved bearing chamber with slope on the return-oil structure， accumulation area of the oil on right side of return-oil port disappeared， volume fraction of the oil in the chamber decreased significantly， resulting in the increasing return-oil efficiency significantly. The combined improvement scheme （ES） can take into account the advantages of embedded and slope improvement schemes， and the return-oil efficiency is further improved. Compared with the conventional bearing chamber， when the oil flow rate is 200L/h and the rotating speed is 15000r/min， the return-oil efficiency of the embedded， slope and combined improvement schemes increases by 16.47%， 13.02% and 32.81%， respectively.