粗糙表面微型气体轴承润滑性能及其转子动力学特性研究  

Surface roughness effects on gas journal microbearing performance and rotordynamic system in microfluidic applications

作　　者：吴垚[1,2] 杨利花 郗文君[3] 张彩丽 毕春晓[4] 王哲 曹巨江 WU Yao;YANG Li-hua;XI Wen-jun;ZHANG Cai-li;BI Chun-xiao;WANG Zhe;CAO Ju-jiang(School of Mechanical and Electrical Engineering, Shaanxi University of Science & Technology, Xi′an 710021, China;State Key Laboratory for Strength and Vibration of Mechanical Structures, Xi′an Jiaotong University, Xi′an 710049, China;Energy Management Low Voltage Division, Schneider Innovation Technology Co., Ltd., Xi′an 710075, China;Institute of Engineering ThermoPhysics, Chinese Academy of Sciences, Beijing 100190, China;School of Materials Science and Engineering, Xi′an Polytechnic University, Xi′an 710048, China)

机构地区：[1]陕西科技大学机电工程学院,陕西西安710021 [2]西安交通大学机械结构强度与振动国家重点实验室,陕西西安710049 [3]施耐德(西安)创新技术有限公司低压事业部,陕西西安710075 [4]中国科学院工程热物理研究所,北京100190 [5]西安工程大学材料工程学院,陕西西安710048

出　　处：《陕西科技大学学报》2022年第2期128-137,共10页Journal of Shaanxi University of Science & Technology

基　　金：国家科技重大专项项目(J2019-IV-0021-0089);国家自然科学基金项目(11872288);陕西省自然科学基础研究计划项目(2022JQ-002);陕西省教育厅专项科研计划项目(20JK0661);陕西省西安市碑林区科技计划项目(GX2005);陕西科技大学引进人才博士科研启动基金项目(2021BJ-11)。

摘　　要：微型气体轴承-转子系统作为微型旋转机械实现功能转换的重要部件,表面粗糙形貌、薄膜润滑性能及转子动力学特性是影响整体设备可靠运转的关键因素.利用Boltzmann稀薄效应模型修正可压缩气体动压润滑Reynolds方程,通过分形理论表征微型轴承表面的粗糙轮廓,研究了气体稀薄效应和表面粗糙度耦合作用下微型轴承的静动态性能.并利用有限元法建立粗糙表面微型气体轴承-转子系统的动力学模型,得到转子系统固有特性和轴心轨迹的变化规律.结果表明:表面粗糙度效应提高了轴承的承载能力和动态刚度系数,在较大轴承数时增加幅度更明显.由于稀薄效应降低了轴承的直接刚度系数,转子振幅随气膜稀薄程度的增加而增大,表面粗糙峰的增加会降低转子系统的固有频率.The aerodynamic lubrication performance of journal microbearing and the rotordynamics of microbearing-rotor system are of great importance to the stability of micro rotating machinery for realizing function conversion.The surface roughness,thin film lubrication problem and rotordynamics are the key factors affecting the safe operation of various microfluidic devices.Based on the Duwensee′s slip correction model and the fractal geometry theory,the interactive effects of gas rarefaction and surface roughness on the static and dynamic characteristics were investigated under various operation conditions and structure parameters.The modified Reynolds equation,which governs the gas film pressure distribution in rough bearing,is solved by employing the partial derivative method.The dynamic model of gas microbearing-rotor system is established by finite element method,and the variety of the natural frequencies and axes trajectories are obtained.The results show that high values of the eccentricity ratio and bearing number tend to increase the principal stiffness coefficients significantly,and the fractal roughness surface considerably affects the ultra-thin film damping characteristics compared to smooth surface bearing.Because the rarefaction effect decreases the direct stiffness coefficients of gas microbearing,the vibration amplitude of the rotor increases with increasing rarefied content of gas,and the increase of the roughness heights will reduce the natural frequency of rotor system.

关 键 词：气体稀薄效应 表面粗糙形貌 超薄气膜润滑 运动方程 转子动力学 

分 类 号：TH133.37[机械工程—机械制造及自动化]