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.