基于滑移模型静压气体轴承数值分析

发布时间：2018-04-12 18:57

本文选题：滑移修正 + 有限体积法　；参考：《上海应用技术大学》2017年硕士论文

【摘要】：考虑滑移效应对静压气体轴承特性的影响,并引入一阶滑移、Wu (2008)新滑移、及二阶滑移修正Reynolds方程。采用有限体积法的混合差分格式来离散连续模型Reynolds方程和一阶滑移、Wu (2008)新滑移、及二阶滑移修正Reynolds方程。而且利用一阶滑移、Wu (2008)新滑移、及二阶滑移速度来修正静压气体轴承各节流孔区域的流出流量。从而根据流量守恒原理,建立无滑移修正及经滑移修正的各节流孔区域流量守恒方程。最终,使用SOR迭代算法联合流量守恒型变步长迭代算法,对小气膜间隙(小于4.0μm)、高转速(大于1.0×104r/min)条件下的静压气体轴承特性进行数值分析。进一步在MATLAB软件平台上,对无滑移模型、一阶滑移、Wu (2008)新滑移、及二阶滑移模型静压气体轴承内部气压进行编程计算。而且在不同的气膜间隙、转速、及偏心率等条件下,通过对比连续模型和一阶滑移、Wu (2008)新滑移、及二阶滑移模型的结果发现:(1)当气膜间隙小于1.0μm时,连续模型严重高估了最小气膜厚度周围的气压、承载力、及最终刚度。而且在最小气膜厚度处,相较于Wu (2008)新滑移模型的结果,一阶滑移模型高估了气压,二阶滑移模型低估了气压分布;(2)连续模型与一阶滑移、Wu (2008)新滑移、及二阶滑移模型预测的承载力、刚度之间偏差随气膜间隙的减小而放大,已无法适用于小气膜间隙条件下的静压气体轴承承载和刚度等特性分析;(3)在小气膜间隙条件下,需使用滑移边界条件来修正静压气体轴承的主控方程和各节流孔区域的流量守恒方程,以便较准确的估算静压气体轴承的压强、承载力、及刚度等力学特性:(4)进一步考虑到物理上的真实性,发现使用Wu (2008)的新滑移模型对主控方程、气流速度分布以及流量进行修正,可以得到较好的静压气体轴承气压、承载、及刚度等特性。这为静压气体轴承性能估算提供了一定的理论基础。
[Abstract]:The influence of slip effect on the characteristics of hydrostatic gas bearing is considered, and a new slip is introduced, and the second-order slip correction Reynolds equation is introduced.The mixed difference scheme of finite volume method is used to discretize the Reynolds equation of continuous model and the first-order slip Wu Wu 2008) new slip, and second-order slip to modify the Reynolds equation.Moreover, the flow rate in the throttle region of the hydrostatic gas bearing is corrected by using the new slip of the first order slip Wu's 2008) and the second-order slip velocity.According to the principle of flow conservation, the flow conservation equations of every throttle with and without slip correction are established.Finally, the characteristics of hydrostatic gas bearings with small film clearance (< 4.0 渭 m) and high rotational speed (> 1.0 脳 10 ~ 4 r / min) are numerically analyzed using SOR iterative algorithm combined with flow conservation variable step size iteration algorithm.Furthermore, the non-slip model, the first-order slip model, the new slip model and the second-order slippage model are programmed on the MATLAB software platform for the calculation of the internal pressure of the hydrostatic gas bearing.Moreover, under different conditions of film clearance, rotational speed and eccentricity, by comparing the continuous model with the first-order slip Wu (2008) slip model, and the second-order slip model, it is found that: 1) when the film gap is less than 1.0 渭 m,The continuous model seriously overestimates the pressure, bearing capacity and final stiffness around the minimum film thickness.Compared with the results of the new slip model, the first order slip model overestimates the pressure, the second order slip model underestimates the pressure distribution and the second order slip model underestimates the pressure distribution at the minimum thickness of the gas film, and the first order slip model and the first order slip model Wu 2008) show that the first order slip model overestimates the pressure, and the second order slip model underestimates the pressure distribution.And the bearing capacity predicted by the second-order slip model, the deviation between stiffness increases with the decrease of the gap of the film, which is no longer suitable for the analysis of the bearing capacity and stiffness of the hydrostatic gas bearing under the condition of small film clearance. (3) under the condition of small film clearance, the bearing capacity and stiffness of the hydrostatic gas bearing can not be analyzed under the condition of small film clearance.In order to estimate the pressure and bearing capacity of hydrostatic gas bearing, it is necessary to modify the governing equation of hydrostatic gas bearing and the flow conservation equation of every throttle region by using slip boundary condition, so as to estimate the pressure and bearing capacity of hydrostatic gas bearing more accurately.Further considering the physical reality, it is found that the new slip model of Wu (2008) is used to modify the main governing equation, the distribution of airflow velocity and the flow rate, and the pressure and load of the hydrostatic gas bearing can be obtained.And stiffness and other characteristics.This provides a theoretical basis for the performance estimation of hydrostatic gas bearings.
【学位授予单位】：上海应用技术大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TH133.36

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