【摘要】 在微纳米尺度下工作的气体薄膜润滑轴承,气膜厚度与气体分子平均自由程较为接近,气体稀薄效应是影响轴承动态特性的关键因素。通过MATLAB的偏微分方程工具箱求解超薄气膜润滑动态Reynolds方程得到动态刚度和阻尼系数,探讨了不同半径间隙,稀薄效应修正模型以及轴承参数对动特性系数的影响。结果表明,随轴承间隙减小,气体稀薄程度增加,气体径向轴承的动态刚度系数显著降低,动态阻尼系数有所增加。当半径间隙降低到纳米尺度时,动态性能受轴承参数的影响较小。更多还原

【Abstract】 In micro-nano-scale,the gas-film thickness of aerodynamic gas-lubricated bearings is close to the mean free-path of gaseous molecules.The gas rarefied effect is a key influence factor to the dynamic performance of self-acting gas bearings.In this paper,the dynamic gas film pressure and film thickness are expressed as the complex form with periodic disturbance of the journal.The dynamic Reynolds equation for the ultra-thin film lubrication is solved in virtue of the toolbox of partial derivative equation(PDE)of MATLAB.Then the dynamic stiffness and dynamic damping coefficients of hydrodynamic gas bearings can be obtained.The effects of different radius clearance,the modified models of gas rarefied effect and different bearing parameters on the dynamic characteristic coefficients of gas bearings are analyzed.The results show that the dynamic stiffness coefficient of aerodynamic journal bearings is significantly reduced and the dynamic damping coefficient is increased as the increase of gas rarefied effect and decrease of radius clearance.Moreover,the parameter of the aerodynamic pressured bearing has a little influence on the dynamic characteristics when the radium of clearances is reduced to nanometer scale.更多还原