三油楔滑动轴承动力特性数值研究

Numerical study on dynamic characteristics of three-lobe journal bearing

应用CFD动网格技术建立了三油楔滑动轴承动力特性求解模型。在验证求解模型准确性的基础上,研究了三油楔滑动轴承的流场特性,流体动压效应形成条件以及楔形度、偏心率、转速、偏位角、供油压力等因素对三油楔滑动轴承动力特性的影响。研究结果表明,随着偏心率的增加,三油楔滑动轴承的收敛楔形间隙逐渐变成发散楔形间隙,不再满足流体动压形成条件,使油膜正压区由3个逐渐变成1个。随着楔形度的增加,刚度系数和交叉阻尼系数变化不大,直接阻尼系数随之减小;随着偏心率的增大,刚度阻尼系数绝对值均随之增大;随着转速增大,直接刚度和阻尼系数变化较小,交叉刚度系数绝对值随之增大;随着偏位角的增大,直接刚度和交叉阻尼系数变化较小,交叉刚度与直接阻尼系数的绝对值均随之减小;供油压力对三油楔滑动轴承刚度阻尼系数影响较小,因此降低楔形度、转速、偏位角,增加偏心率将更有利于转子的稳定性。

A solving model of the dynamic characteristics of three-lobe journal bearings w as established by CFD technology. After the accuracy w as verified,the model w as used to investigate the flow characteristics of three-lobe journal bearings,the formation of hydrodynamic action and effects of w edge degree,eccentricity,inlet pressure,and rotational speed. The results show that w ith the increase of eccentricity,gaps of the lobes get big gradually,w hich cannot form hydrodynamic action and make the three positive pressure areas of oil film become one area. Stiffness coefficient and cross damping coefficient remain relatively unchanged,w hile direct damping coefficient decreases w ith the increase of w edge degree. Absolute values of stiffness and damping coefficients increase as the eccentricity ratio increases. With increasing rotational speed direct stiffness and damping coefficients have no obvious change,but absolute value of cross stiffness increases.Both cross stiffness and direct stiffness change slightly,and their absolute values decrease as attitude angle increases. Oil supply pressure has a minor effect on stiffness and damping coefficients. Therefore,the decrease of w edge degree,rotational speed and attitude angle and the increase of eccentricity are good for stability of the rotor.