稀薄效应对动压气体轴承静动特性的影响

为研究稀薄效应对微小间隙下动压气体轴承静动态特性的影响,分别采用连续模型、一阶滑移模型以及在任意克努森数下都与线性玻尔兹曼方程解有较高吻合的WU新滑移模型,基于有限体积法建立考虑稀薄效应的静动态Reynolds方程,给出3种模型下轴承静态承载力与偏心率、轴颈扰动频率与轴承动特性系数的变化关系。数值分析结果表明:随偏心率的变化,连续模型预测的静态承载力最大,一阶滑移次之,WU新滑移模型预测的值最小;随着扰动频率的增加,考虑滑移模型计算的主刚度系数和主阻尼系数均有减小的趋势,且WU新滑移模型计算的主刚度系数和主阻尼系数明显低于连续模型和传统的一阶滑移模型。传统连续模型和一阶滑移模型过高地估计了轴承的静动特性系数,WU新滑移模型计算的结果更为准确。

Effect of Rarefied Gas Effect on Static and Dynamic Characteristics of Micro Self-Acting Bearings

In order to study the influence of rarefied gas effect on the static and dynamic characteristics of self-acting bearing with small clearance,the static and dynamic Reynolds equations considering rarefied gas effect were established respectively based on the finite volume method,by using the continuous model,the first-order slip model,as well as the Wu new slip model which is in good agreement with the solutions of linear Boltzmann equation under any Knudsen number.The relationship between static bearing capacity and eccentricity,and the relationship between disturbance frequency and dynamic characteristic coefficient of micro self-acting bearing under three models were given.The results of numerical analysis are as follows,with the change of eccentricity,the static bearing capacity predicted by the continuous model is the largest,the first order slip is the second,and the predicted value by the new WU slip model is the smallest.With the increase of disturbance frequency,the principal stiffness coefficient and principal damping coefficient calculated by the slip models tend to decrease,and the principal stiffness coefficient and principal damping coefficient calculated by the new WU slip model are obviously lower than those by the continuous model and the traditional first-order slip model.The static and dynamic characteristic coefficients of bearings are overestimated by the traditional continuous model and the first-order slip model,and the results of the new WU slip model are more accurate.