空气静压导轨气浮支撑振动特性研究

发布时间：2018-07-09 16:23

本文选题：空气静压导轨 + 自激振动　；参考：《昆明理工大学》2017年硕士论文

【摘要】：空气静压导轨具有低摩擦,高精度,清洁无污染等优点,被广泛应用于IC制造、三坐标测量机、精密制造等设备中。传统对空气静压导轨的研究主要对空气静压导轨的静态特性(如承载力、静刚度等)进行研究。通过求解气膜流动的N-S方程,得到满足使用要求的结构参数和工作条件。随着精度要求的不断提高,当空气静压导轨气膜间隙降至10μm以下时,基于稳态流动和层流假设的研究方 ·法受到挑战,气浮支撑内部的自激振动成为制约静压导轨进一步发展的关键问题。本文基于冲击射流理论,建立单自由度轴承自激振动模型,求得系统的振动微分方程,利用大涡模拟(LES)方法结合实验研究,对润滑气膜内的流态进行分析。通过对气浮微振动形成机理的深入研究,丰富空气静压导轨设计和分析的理论方法和研究经验。本文主要研究内容如下:(1)基于冲击射流理论,建立空气静压导轨湍流高压区的流动分区模型。根据流场内速度矢量特征和压力分布规律,将进气孔附近高压湍流区域划分为:自由射流区、滞止区、过渡区和出口壁面射流区。明确各区域的流动特性和能量传递特征,给出各区域相应的控制方程。并明确提出引起气膜波动的成因与主旋、次旋和出口涡量之间的关系。(2)借助有限元分析软件,对气膜微振动问题进行数值分析。首先,利用雷诺平均数值模拟(RANS)方法求得气浮支撑流场稳态解,作为保证流场迭代稳定收敛的初始值;然后,利用三维大涡模拟(3DLES)方法分析不同时刻流场的特征,将气旋形成和涡脱的瞬态过程与气膜波动联系到一起,从动态的角度揭示微振动成因;接下来分析气旋的强度、移动速度和稳定位置对气膜微振动的影响;最后得到不同工作参数和结构参数对气膜微振动强度的作用效果和影响规律。(3)搭建空气静压导轨微振动实验测试平台,验证理论分析和数值计算结果的可靠性和有效性,并对实验误差进行了分析。观测不同工作参数和结构参数下轴承内部非线性自激微振动的固有频率、时均振幅,验证气膜内气旋现象与轴承非线性自激振动之间的关系。
[Abstract]:Air static pressure guideway has the advantages of low friction, high precision, clean and pollution-free, and is widely used in IC manufacturing, CMM, precision manufacturing and so on. The traditional research on aerostatic guide rail is mainly focused on the static characteristics (such as bearing capacity, static stiffness, etc.) of the aerostatic guide rail. By solving the N-S equation of gas film flow, the structure parameters and working conditions are obtained. With the improvement of precision, the research method based on steady flow and laminar flow assumption is challenged when the gap of air film decreases to less than 10 渭 m. The self-excited vibration inside the air-bearing support is a key problem restricting the further development of the hydrostatic guideway. Based on impinging jet theory, the self-excited vibration model of single degree of freedom bearing is established, and the vibration differential equation of the system is obtained. The flow state in lubricating gas film is analyzed by means of large eddy simulation (les) method combined with experimental study. Through the deep research on the formation mechanism of air flotation micro vibration, the theoretical method and research experience in the design and analysis of air static pressure guideway are enriched. The main contents of this paper are as follows: (1) based on impinging jet theory, a flow zonation model of turbulent high pressure region of air static guideway is established. According to the characteristics of velocity vector and pressure distribution in the flow field, the high pressure turbulent region near the inlet pore is divided into free jet zone, stagnation zone, transition zone and exit wall jet region. The flow characteristics and energy transfer characteristics of each region are clarified, and the corresponding governing equations of each region are given. The relationship between the cause of film fluctuation and the principal rotation, secondary rotation and exit vorticity is put forward. (2) with the help of finite element analysis software, the film micro-vibration problem is numerically analyzed. Firstly, the Reynolds mean numerical simulation (rans) method is used to obtain the steady state solution of the flow field supported by air floatation as the initial value to ensure the steady convergence of the flow field, and then the 3D large eddy simulation (3DLES) method is used to analyze the characteristics of the flow field at different times. The transient process of cyclone formation and vortex detachment is connected with the film fluctuation to reveal the causes of micro-vibration from the dynamic point of view, and then the influence of cyclone intensity, moving speed and stable position on the film micro-vibration is analyzed. Finally, the effects of different working parameters and structural parameters on the micro vibration intensity of the gas film are obtained. (3) the experimental test platform for the micro vibration of the air static guide rail is built to verify the reliability and validity of the theoretical analysis and numerical calculation results. The experimental error is analyzed. The natural frequency and time-averaged amplitude of nonlinear self-excited micro-vibration in bearing under different working parameters and structural parameters were observed to verify the relationship between the phenomenon of cyclone in film and the nonlinear self-excited vibration of bearing.
【学位授予单位】：昆明理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TH113.1

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