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1. 浙江大学流体动力与机电系统国家重点实验室, 杭州 310027;
2. 中航工业金城南京机电液压工程研究中心, 南京 211106

Analysis on aircraft cylinder seal property based on mixed lubrication theory
OUYANG Xiaoping1 , XUE Zhiquan1, PENG Chao1, GUO Shengrong2, ZHOU Qinghe2, YANG Huayong1
1. State Key Laboratory of Fluid Power & Mechatronic Systems, Zhejiang University, Hangzhou 310027, China;
2. Nanjing Engineering Institute of Aircraft Systems, Jincheng, AVIC, Nanjing 211106, China
Abstract: Aimed to investigate the influences of working conditions such as different pressures, temperatures and velocities on the performance of the seal of the aircraft cylinder, the Turcon VL seal from Trelleborg AB was analyzed based on the mixed lubrication theory. The macro and micro multi-field coupling model based on the mixed lubrication theory was built, which mainly includes fluid model with cavitation and fluid factors in Reynolds equation, micro contact model of Greenwood-Williamson(G-W) and heat transfer model of Fourier. By computing the model with finite volume method, the characteristics of macro contact pressure, micro contact pressure and oil pressure distribution under different fluid pressures were analyzed. The research results show that the seal leakage and friction increases nearly linearly with the fluid pressure increasing, the seal has no leakage at 25℃ but has some at 135℃, and the seal friction decreases but leakage increases with the cylinder velocity increasing.
Key words: aircraft cylinder     VL seal     mixed lubrication model     multi-field coupling     finite volume method
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1 建 模

 图 1 航空液压作动器简图 Fig. 1 Sketch of aircraft hydraulic cylinder

 图 2 密封面接触状态 Fig. 2 Contact state of sealing interface

1.1 宏观接触模型

 图 3 Turcon VL密封宏观接触模型 Fig. 3 Macro contact model of Turcon VL seal
1.2 油膜模型

1.3 微观接触模型

1.4 变形模型

1.5 传热模型

1.6 多场耦合模型

 图 4 计算流程 Fig. 4 Computational procedure
2 航空作动器密封性能分析 2.1 压力对作动器密封性能影响

 图 5 不同流体压力下的宏观接触压力 Fig. 5 Macro contact pressures at different fluid pressures

 图 6 35 MPa压力分布(内冲程) Fig. 6 Distribution of pressure 35 MPa (instroke)

 图 7 不同流体压力下的油膜压力(内冲程) Fig. 7 Oil film pressures at different fluid pressures(instroke)

 图 8 不同流体压力下的微观接触压力 Fig. 8 Micro contact pressures at different fluid pressures

 图 9 不同流体压力下油膜厚度(内冲程) Fig. 9 Oil film thicknesses at different fluid pressures(instroke)

 图 10 不同流体压力下泄漏量 Fig. 10 Leakages at different fluid pressures

 图 11 不同流体压力下摩擦力 Fig. 11 Frictions at different fluid pressures
2.2 温度对作动器密封性能影响

 图 12 高温与常温压力对比(内冲程) Fig. 12 Pressure comparison between high temperature and normal temperature(instroke)

 图 13 高温与常温油膜厚度对比 Fig. 13 Oil film thickness comparison between high temperature and normal temperature
2.3 作动速度对作动器密封性能影响

 图 14 不同作动速度下油膜厚度对比 Fig. 14 Oil film thickness comparison among different velocities

 图 15 不同作动速度下泄漏量对比 Fig. 15 Leakage comparison among different velocities

 图 16 不同作动速度下摩擦力对比 Fig. 16 Friction comparison among different velocities
3 结 论

1) 高压降低密封性能,增大泄漏且加剧摩擦磨损,缩短密封寿命。因此压力越高,对密封挑战越大。

2) 高温通过降低流体黏度,大幅增加泄漏且加剧摩擦磨损。高温与摩擦生热效应形成正反馈,使工作温度更高,密封效果更差。

3) 高速作动会导致泄漏量增多,而低速作动不易形成油膜,摩擦加大。在航空作动器启动与停机时,摩擦最大,磨损最严重,而作动速度提升后泄漏量会有增大。

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#### 文章信息

OUYANG Xiaoping, XUE Zhiquan, PENG Chao, GUO Shengrong, ZHOU Qinghe, YANG Huayong

Analysis on aircraft cylinder seal property based on mixed lubrication theory

Journal of Beijing University of Aeronautics and Astronsutics, 2016, 42(2): 251-257.
http://dx.doi.org/10.13700/j.bh.1001-5965.2015.0387