Development of fast and accurate Software of Dynamic Journal Bearings

通常计算出的动特性系数存储在数据库中，并用于滑动轴承的设计。然而，数据量随着诸如L/D比和轴承类型的参数数量的增加而变得更大。因此，在这些情况下，使用数据库几乎变得不切实际。这就是为什么我们开发了快速准确的软件来获得径向轴承的动态系数。1)雷诺方程的矩阵形式（压力的正交函数展开）。将该方法应用于径向滑动轴承油膜力的求解。由于该方法在边界线平行于坐标轴时有效，因此引入了准Reynolds边界条件，在此条件下，尾边界线由一条直线给出，并保证通过这条直线的整体流动是连续的。结果表明，准Reynolds边界条件可以很好地近似Reynolds边界条件，且计算时间比一般的有限差分法要短。2）有限宽滑动轴承准Reynolds边界条件动力系数的快速计算方法。将该方法应用于滑动轴承的动力学问题，在得到静油膜力后，通过少量的矢量计算，得到油膜力对偏心率、姿态角和时间的导数。3）有限宽滑动轴承阻尼系数的交叉项。有限宽滑动轴承线性阻尼系数的交叉项彼此相等，即，Cxy=Cyx，采用求解雷诺方程1），2）的一般方法。

Usually calculated dynamic coefficient are stored as a database and the database is used in designing journal bearings. However, an amount of the data becomes larger with increase in number of parameters such as L/D ratio and bearing type. Therefore, in these cases, the use of database becomes almost impractical. This is the reason why we develop fast and accurate software for obtaining dynamic coefficients of journal bearings.? 1)Matrix Form of Reynolds Equation,(Expansion of Pressure by Orthogonal Functions). The method is applied to obtaining the static film forces of journal bearings. As this method works effectively when boundary lines are parallel to coordinate axes, a quasi-Reynolds boundary condition is introduced.Under this condition,the trailing boundary line is given by a straight line and the bulk flow across this line is ensured to be continuous. It is shown that so-called Reynolds condition can be satisfactorily approximated by the quasi-Reynolds condition, and the time required by the calculation is such less than that required by ordinary finite difference method.2)A Fast Method for Calculating Dynamic Coefficients of Finite Width Journal Bearings With Quasi Reynolds Boundary Condition. The method is applied to the dynamic problems of journal bearings.The derivatives of the film forces with respect to eccentricity ratio, attitude angle, and with respect to their time are obtained by small number of vector calculations after obtaining the statiefilm forces.3)On the Cross Terms of the Damping Coefficients of Finite Width Journal Bearings. The cross terms of the linear damping coefficients of finite width journal bearings are equal to each other i.e., Cxy=Cyx,the general approach for solving the Reynolds equation 1),2) is used.