气体润滑弹性波箔片轴承动态特性分析
Dynamic characteristics analysis of bump foil journal bearings with air lubrication
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摘要: 通过摄动方法并结合气体润滑压力控制Reynolds方程和气膜压力、气膜厚度及箔片变形等变量的Taylor展开式,推导出弹性波箔片轴承气膜动力特性系数计算微分方程组.同时,考虑气体可压缩性等因素,建立气膜厚度、箔片变形和气膜压力三者之间关系的数学模型方程组.运用Newton-Raphson迭代法和有限差分法耦合求解气膜动力特性系数计算微分方程组和气膜厚度数学模型方程组,得到弹性波箔片轴承气膜刚度和阻尼等动力特性系数随偏心率、转速、扰动频率及轴承长径比等参数变化的规律特性,为箔片轴承设计、优化和弹性波箔片轴承-转子系统理论及试验分析奠定基础.计算结果表明,随着偏心率和转速的增大,润滑气膜主刚度均有不同程度的提高,同时,润滑气膜刚度和阻尼的大小与扰动频率关系密切.Abstract: Differential equations of air film in elastic bump foil journal bearing were deducted by the perturbation method with air lubrication Reynolds equation and series expansions of air film,air film thickness and foil deformation.The mathematics model of the relations among air film thickness,bump foil deformation and air film pressure was developed in consideration of air compressibility.Both finite difference method and Newton-Raphson method were applied to solve the coupled differential equations and air film thickness mathematics model equations,while the variation rules of air film stiffness and damping coefficients were achieved with different eccentricities,speeds,perturbation frequencies and different length-diameter ratios.This provides a basis for bump foil journal bearing design,optimization and theoretical and test analysis of rotor-elastic foil bearing system.The numerical results show that the main air film stiffness is enhanced when eccentricity and speed increase,and the value of air film stiffness and damping of bump foil journal bearing are connected strongly with the perturbation frequencies.
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