表面形貌对浮动式箔片气膜密封性能的影响分析  

Impact Analysis of Surface Morphology on Floating Foil Film Sealing Performance

作　　者：徐洁 俞树荣[1] 杨小成 丁雪兴[1] 蒋海涛 XU Jie;YU Shurong;YANG Xiaocheng;DING Xuexing;JIANG Haitao(College of Petrochemical Engineering,Lanzhou University of Technology,Gansu Lanzhou 730050,China)

机构地区：[1]兰州理工大学石油化工学院,甘肃兰州730050

出　　处：《摩擦学学报》2023年第11期1341-1352,共12页Tribology

基　　金：国家重点研发计划项目(2020YFB2010000);宁波市科技创新2025重大专项(2020Z112);兰州理工大学研究生科研探索创新项目资助。

摘　　要：为揭示密封副表面形貌对浮动式箔片气膜密封性能的影响规律,以一端固定式波箔片的织构化浮动式箔片气膜密封为研究对象,通过三维W-M分形函数表征设计有三角形织构的粗糙平箔片表面,在考虑微通道尺度效应、流固界面台阶效应和弹性面变形问题的同时,建立了楔形气膜和运动转子同步旋转的压力控制方程,并采用有限差分法耦合求解,得到分形参数对流场润滑状态和密封特性的影响规律.研究结果表明:表面粗糙峰对密封性能的影响是单调的,而表面密集度对密封性能的影响是不规则的;特征尺度系数G的增大和一定范围内分形维数D的减小,可在提高密封动压效应和降低泄漏率方面发挥积极作用,反之则有利于减小摩擦力和实现密封系统的稳定;摩擦副的真实表面对密封性能的影响不可忽略,但随着气膜厚度的增大,影响程度会被逐渐削弱.本文中的研究使浮动式箔片气膜密封的理论研究更接近真实工况,可为弹性箔片的制造工艺提供一定参考.Floating foil seal is a new non-contact seal structure,which is proposed to meet the sealing requirements of the rocket turbine pump and the main bearing of aero-engines.Specifically,elastic foil with adaptive deformation ability is designed based on the cylindrical gas film seal,with the rigid sealing surface being replaced.In this way,the antiinterference ability of the system can be improved.Research in this regard mostly takes the sealing friction pair as a smooth surface,but in practice,a completely smooth surface does not exist,as any friction interface is composed of many different micro convex bodies and micro pits.On the surface of the friction pair,the dynamic pressure pits or dynamic pressure grooves are usually designed to improve the dynamic pressure effect and friction performance.After re-processing,the working surface tends to exhibit varied surface characteristics,meaning that the accurate control of the groove shape and roughness remains a topic of exploration for high-precision machining technology.In fact,whether it is a gas seal or other mechanical parts,the true shape of the friction pair surface should not be completely ignored under certain circumstances.In order to investigate how the surface topography of the sealing pair affecting the floating foil sealing performance,this work studied the textured floating foil gas film seal of one end fixed bump foil.The detailed experiments were as follows:the rough flat foil surface with triangular texture was characterized by the three-dimensional W-M fractal function.The pressure control equation for the synchronous rotation of the wedgeshaped gas film and the moving rotor was established,with the micro-channel scale effect,the fluid-solid interface step effect,and the elastic surface deformation had been taken into account.The finite difference method was used to solve the coupling problem,then,the effects of fractal parameters on the lubricating state of the flow field and sealing characteristics were obtained.By changing the characteristic scal

关 键 词：W-M函数 分形参数 弹性箔片 气体润滑 密封特性 

分 类 号：TH117.2[机械工程—机械设计及理论]