表面粗糙度对航空液压作动器密封性能的影响

航空液压作动器普遍应用在飞机机翼、舱门、起落架等部位,往复密封为其典型密封形式,密封失效会 严重影响飞机任务的执行和飞行安全。密封副表面粗糙度是重要的工程可控参数且对于密封性能的影响很 大,因此分析表面粗糙度对作动器密封性能的影响具有重要的理论和实际意义。建立适用于往复组合密封的 确定性混合润滑数值仿真模型,并与有限元分析方法结合计算膜厚值,分析密封圈表面粗糙的幅值和波长变化 以及运动速度和液压油黏度变化对密封圈润滑性能和密封性能的影响。结果表明:正弦粗糙表面的幅值和波 长增大,会引起油膜压力和油膜厚度波动的幅值增大,但会减小摩擦系数;正弦粗糙表面的幅值增大,有利于减 小密封间隙的最小膜厚和泄漏量,但是波长变化的影响作用不大;液压油黏度和活塞运动速度增大,有利于增 大密封间隙油膜厚度,但会增大泄漏量和摩擦系数。

Influence of Surface Roughness on Seal property of Aircraft Actuator

Aviation hydraulic actuator is widely used in many parts such as aircraft wing, landing gear, hatch door, etc. The typical seal form is reciprocating seal, and the failure of seal will seriously affect the execution of flight mission and even flight safety. Therefore, simulation of seal has important theoretical and practical significance. This paper establishes a deterministic mixed lubrication numerical model for reciprocating combined seal, the fluid-solid coupling analysis is realized by combing finite element method (FEM) with fluid dynamics analysis. The effects of surface roughness and operating conditions on lubrication and sealing performance are investigated. The results show that increase of roughness and wavelength of three-dimensional sinusoidal rough surface can contributes to the increase of fluctuation amplitude of film thickness and pressure, and the reduction of friction. Increasing of amplitude of the sinusoidal rough surface is beneficial to the reduction of the minimum film thickness and leakage. However, the wavelength change has little effect on the minimum film thickness.