弹性元件对大型可倾瓦轴承静动特性的影响

为提高舰船运载机组稳定性, 并有效抑制振动, 在机组推进轴系中采用了一种可倾瓦轴承支点弹性技术(瓦块支点安装有蝶形弹簧), 以某大型燃气轮机为对象, 在轴系四瓦可倾瓦轴承瓦块支点处引入蝶形弹簧结构, 并采用流固热耦合计算模型和轴承多场分析技术, 分析了可倾瓦轴承的温度场、压力场、刚度与阻尼等特性参数, 研究了支点弹性技术对大型可倾瓦轴承摩擦学与动力学特性的影响规律。计算结果表明: 在3 000r·min^-1工作转速下, 刚支结构时可倾瓦轴承最大油膜压力为6.5MPa, 弹支结构时最大油膜压力为6.7MPa, 弹支结构相比刚支结构轴承油膜压力略有上升, 此时2种支点结构轴承的温度变化不大, 最高温度分别为98.95℃与98.85℃; 随着转速的增大, 2种支点结构可倾瓦轴承的主刚度均呈下降趋势, 而其交叉刚度只在±0.1MN·m^-1范围内变化; 在3 000r·min^-1下, 弹支结构轴承主刚度为3.5GN·m^-1, 主阻尼为6MN·s·m^-1, 相比刚支结构轴承主刚度提高了59%, 主阻尼提高了39%。可见: 可倾瓦轴承采用瓦块支点弹性技术, 轴承温度变化不大, 最高油膜压力略有增加, 轴承主刚度和主阻尼明显提高, 这对增加稳定性和抑制振动十分有利。

Influence of elastic element on static and dynamic characteristics of large tilting pad bearing

In order to improve the dynamic stability of warship unit and restrain vibration effectively, a new technology of pivot elasticity was applied to the tilting pad bearing structure of warship propulsion shafting system, and the butterfly spring was mounted at the pad pivot of tilting pad bearing. A large gas turbine was taken as an object, the pivot elasticity structure was introduced into the four tilting pad bearings of large scale shaft, the temperature field, pressure field, stiffness and damping of tilting pad bearing were analyzed by using the fluid-solid-heat coupled model and the multi-field analysis technology, and the effect law of pivot elasticity technology on the tribology and dynamics behavior of tilting pad bearing were investigated. Analysis result shows that when the rotating speed is 3 000 r·min-1, the maximum oil film pressure of rigid pivot bearing is 6.5 MPa, and the maximum oil film pressure of spring pivotbearing is 6.7 MPa and just increases a little compared with rigid pivot bearing. Meanwhile, the highest temperatures of two kinds of pivot structure bearings are 98.95 ℃ and 98.85 ℃, respectively, so the pivot elasticity technique has little effect on the bearings temperatures. With the increase of rotating speed, the main stiffnesses of two kinds of bearings decrease, but their cross stiffnesses change only in the range of ±0.1MN·m-1. At the rotating speed of 3 000 r·min-1, the main stiffness and the main damping of spring pivot bearing are 3.5 GN·m-1 and 6 MN·s·m-1, respectively, which are 59% and 39% higher than the values of rigid support bearing. Obviously, the utilization of pivot elasticity technology has little effect on the bearing temperature, the maximum oil film pressure increases slightly, but the main stiffness and main damping of bearing increase obviously, which is favorable for the stability increase and vibration suppression of warship unit.