不同流型下轴承腔中油气介质的流动特征参数

Characteristic Flow Parameters of Oil/Air Lubricants in Bearing Chamber Under Different Flow Patterns

航空发动机轴承腔两相介质流动状态的理解对于润滑和二次空气流动系统的设计是十分重要的。借助于流型分类进行两相介质流动研究,是揭示轴承腔中两相介质流动物理本质的可行途径。由于航空发动机轴承腔润滑状态的复杂性,难以从物理试验直观判断流型类别,通过流动特征参数的差异性判断流型类别是值得探索的方法。发动机轴承腔可能出现的流型有均相流动、分层流动和油膜/空气(含油滴颗粒相)流动。针对这3种流型类别,分析了润滑介质压力和速度相对于不同流型表现出的差异性及其分布特点,同时探讨了转子转速、供油量和密封进气量等工况条件对这种差异性的影响。研究工作表明:轴承腔中润滑介质的压力和速度可以作为判别两相介质流型的特征参数,并且这一判别技术具有较好的鲁棒性。

A sufficient comprehension about the oil/air two-phase flow in the bearing chamber of an aero-engine is important for the design of its lubrication and secondary air system.The oil/air two-phase flow conditions in the bearing chamber can be studied via flow pattern classification,which is a feasible way to reveal the physical nature of two-phase flows in bearing chambers.However,flow pattern classification is difficult to perform directly by experiments owing to the extremely complex flow conditions in the bearing chamber of an aero-engine.Therefore,it is worthwhile to determine the flow pattern according to the difference of characteristic flow parameters.The oil-gas two-phase flow pattern in bearing chamber of aero-engine may include homogeneous flow,stratified flow and film/gas（oil particle-phase）flow.This article gives a contribution to this subject.An analytical approach is adopted to study the diversities of lubricant pressure and velocity and their distributions under different flow patterns.Furthermore,the influences of rotational speeds,oil flows and sealing air flows on these differences are investigated.The work indicates that lubricant pressure and velocity in the bearing chamber can be regarded as robust characteristic parameters to determine the flow pattern.