随机扰动高速气浮轴承时变刚度和可控阻尼协调维稳与主动控制策略

In order to research the film whirl and film oscillation of hydrostatic-dynamic gas bearings when it occurs breakthrough critical speed, instability occurs owing to bifurcation, unpredictable state because of chaos, the project breaks through the traditional weighted analysis method of gas bearings capability considered the effect of hydrodynamic and hydrostatic mutual coupling, the transient Reynolds equation and the 3D lubrication analysis mathematical model of the hydrostatic-dynamic gas bearings were established, and the numerical solution method was derived to calculate unsteady gas film force and nonlinear dynamic characteristics coefficients. The project will research the influence laws of disturbance frequency on transient film stiffness and damping in order reveal the connection between transient dynamic characteristics coefficients and critical rotational speed, whirl shape and whirl energy.The quantitative relationship between dynamic stiffness and damping coefficients and the critical rotational speed of film whirl was established to explore the nonlinear dynamics behavior and the mechanical mechanism of stability. The effect of nonlinear dynamic characteristics on promoting whirl or maintaining stability was researched, in order to explore transient film stiffness and damping the mechanisms for coordinating maintenance of stability of time-varying stiffness and controllable damping. By generating effect of tangential gas additional circulation, gas film dynamic characteristics was reconstructioned. The system natural frequency and whirl frequency was transformed. It would help to discovery the real-time forecasting and the control strategies of gas bearing instability. The project provide a theoretical prediction and active control method to improve the stability of gas bearing in complex environment.

本项目针对高速动静压气浮轴承突破临界转速、分叉产生失稳或进入混沌不可预测状态时产生的气膜涡动和气膜振荡问题，突破传统性能分析中的简单叠加，考虑动压和静压相互耦合效应，建立动静压混合气浮轴承瞬态雷诺方程、三维气膜瞬态流场分析模型和数值求解方法，计算非稳态气膜力、非线性动态特性系数。研究扰动频率对气膜瞬态刚度和阻尼系数的影响规律，研究轴承动态特性系数与涡动临界转速、涡动形状和涡动能量之间的关系，建立动态特性系数与气膜涡动时轴颈临界转速的定量关系，探索气浮轴承瞬态非线性动力学行为和轴承稳定性的力学机理。研究气膜的非线性动态特性联合作用对轴心运动的促涡和维稳，探索时变刚度和可控阻尼协调维稳的机理，通过产生切向气附加环流效应重构气膜动态特性，改变系统固有频率和气膜涡动频率之间的耦合关系，发现遏制气浮轴承失稳的实时预报方法和控制策略。为气浮轴承在复杂的运行环境中提高稳定性，提供理论预测和主动控制。

项目针对高速动静压气浮轴承突破临界转速、分叉产生失稳或进入混沌不可预测状态时产生的气膜涡动和气膜振荡问题，突破传统性能分析中的简单叠加，考虑动压和静压相互耦合效应，建立动静压混合气浮轴承瞬态雷诺方程、三维气膜瞬态流场分析模型，构建气膜间隙瞬态压力分布、非线性气膜力、稳态承载性能和非线性特性系数的数值求解方法。主要研究了混合气体轴承气体动压和静压的耦合效应，随机扰动下气体轴承结构参数和运行参数变化气体轴承瞬态刚度和阻尼系数变化规律，模拟在不平衡偏心率与不同转速下轴心瞬态涡动运动轨迹，探索了气膜稳定性问题的力学机理；研究了轴承气膜非线性动态特性对轴承转子系统稳定性的综合作用，通过产生切向气附加环流效应重构气膜动态特性，改变系统固有频率和气膜涡动频率之间的耦合关系，探索了时变刚度和可控阻尼协调维稳的机理；建立了动静压混合轴承动态稳定性试验系统，探索了动静压气体轴承瞬态非线性动态特性系数的识别方法，进行动静压气体轴承动态性能试验测试，分析供气压力、转速、外部载荷、涡动频率变化对轴承动态特性系数和稳定性的影响规律，研究了气浮轴承动态失稳过程中，分叉、混沌等时变非线性动态特性与动态稳定性之间的关联关系，研究了以供气压力和切向角为系统的控制变量，主动控制轴承运行时的刚度和阻尼重构气膜的动态特性的策略。项目研究为气浮轴承在复杂的运行环境中提高气膜承载性能、优化气膜动态特性、减小气膜涡动和提高气体轴承运行稳定性提供理论基础和主动控制方法。项目研究成果成功应用在航空航天、精密仪器、高速空气主轴、高速鼓风机和制冷机上使用的高速高精密气体轴承设计与性能测试中。