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621.
针对高温环境下轴承材料性质和润滑状态变化,造成轴承磨损加剧,过早丧失精度的问题。首先开展高温环境下轴承用材料的摩擦磨损试验,获取材料的磨损系数。在此基础上,考虑温度、润滑、轴承材料属性等对轴承磨损性能的影响,建立高温角接触球轴承磨损模型,通过数值求解探讨工况参数和结构参数等对轴承磨损性能的影响,并评估轴承的磨损寿命。结果表明:对于高温轴承材料无磁合金GH05,在高温300 ℃摩擦状态下平均磨损系数为2.5×10-7 mm2/N;随着载荷、转速、温度的增加,轴承内、外滚道的磨损率均不断增大,其中内圈磨损率大于外圈,内圈磨损特性决定着轴承的磨损寿命;载荷和转速是决定轴承磨损寿命的主要因素,轴承主结构参数对磨损寿命具有重要影响,通过结构优化可提高轴承磨损寿命。 相似文献
622.
623.
《中国航空学报》2023,36(2):377-387
For designing efficient lubrication system of an aeroengine bearing chamber, sufficient knowledge on oil/air two-phase flow characteristics is required. When analyzing bearing chamber two-phase flow, the essential prerequisite is quantifying the oil ligaments, which are detached from bearing rotary elements and shed into the bearing chamber. Related investigations are mainly targeted at liquid shedding on the rotating disk as opposed to the bearing rotary elements. Moreover, the research based on bearing rotary elements is conducted by experiment. Due to the limited operating conditions, experimental studies cannot guide engineering applications. To overcome these limitations, a theoretical model is established in this paper, for revealing the mechanism of oil shedding from bearing rotary elements and quantifying the shedding ligaments. The theoretical model is validated against experimental results from classical studies. In addition, the correlation for shedding ligaments number based on aeroengine bearing structural and operational parameters is obtained via theoretical analysis. The analytical results demonstrate that oil shedding and ligaments formation appear at the edge of bearing inner race outer-periphery. The number of shedding ligaments increases with the rise of shaft rotational speed while decreases with the growth of oil viscosity. 相似文献
624.
Xingxing JIANG Qiang HUANG Changqing SHEN Qian WANG Kun XU Jie LIU Juanjuan SHI Zhongkui ZHU 《中国航空学报》2022,35(1):348-364
As critical components in modern aerospace productions, rolling element bearings(REBs) generally work under varying speed conditions, which brings great challenges to their operating health monitoring. Some novel time–frequency decomposition(TFD) algorithms are established recently to extract nonlinear features from the non-stationary signals effectively, which are promising for realizing fault diagnosis of REBs under varying speed conditions. However, numerous personal experiences must be incor... 相似文献
625.
《中国航空学报》2022,35(11):235-251
This paper explores an analytical model for Elastic Ring Squeeze Film Damper (ERSFD) with thin-walled ring and turbulent-jet orifices, and uncovers its Oil Film Pressure Performance (OFPP). Firstly, the ring deformation is addressed by using the Fourier series expansion approach and the orifice outflow rate is characterized with the Prandtl boundary layer theory. Secondly, applying finite difference scheme, the influence of elastic ring flexibility, orifice diameter, and attitude angle on the OFPP is analyzed. Finally, Outer chamber pressure was measured experimentally at different rotor speeds. The results indicate that the outer chamber pressure coats an individual load-carrying region and spreads symmetrically pertaining to the attitude angle. Its amplitude drops as the elastic ring flexibility decreases but boosts with the reduction of the orifice diameter. For inner chamber pressure, the orifice diameter effects a similar trend to the outer cavity, but exhibits more stable distribution regarding the attitude angle. Minimizing the elastic ring flexibility causes an increase in amplitude. The model is validated by the test results giving that the outer chamber pressure shifts synchronously and periodically with the variation of the attitude angle, while the pressure amplitude increases slightly at higher rotor speeds. 相似文献
626.