Dynamic Characteristics Research On Single Disk Rotor System With Oil Leakage Condition

Rotating machinery is one of the most widely used machines in industry, and most of the rotary machinery such as steam turbine, compressor, aero engine and so on, have hollow cavity structure. Because of the weak seal of device or the defective assembly, rotating cavity of the rotor system often stores or suffers the leakage oil, which finally turns into the oil leakage rotor system. In some specified cases, the oil in the cavity can cause a strong self-excited vibration of the system, which will bring great loading force to the support structure, meanwhile, the cavity will suffer great deformation, resulting in rub of the rotor and stator, even the destruction of mechanical structure. Therefore, it is of great significance for long-term stable operation of the rotating machine to explore the dynamic characteristics of oil leakage rotor system.In this paper, we consider the single disk rotor system with oil leakage condition as main research objective. On the base of the fluid simulation and experimental verification, change rules of the oil shape are obtained. Mechanical model of single disk rotor system with oil leakage condition is established based on the simplification of oil body and Lagrange equation. The dynamic characteristics of the oil leakage rotor system are analyzed by numerical analysis method. The main work includes the followings:(1) Based on the model of single disk rotor system with oil leakage condition, the 2D model of oil-disk fluid simulation is established. Then Gambit, which is specifically aimed at mesh generation, is used to obtain the fluid simulation structural mesh of oil-disk by the multi-block and boundary refinement technique.(2) Based on the Volume of Fraction (VOF) model and statistic pressure monitor in the Fluent software, influence of rotating eccentricity, liquid type, liquid volume and the rotating speed of the disk, four parameters to the rotating shape of oil is analyzed, then by means of the rig of single disk rotor system with oil leakage condition, the fluid simulation results are verified by experiment.(3) Based on the mechanical simplification of liquid oil, five degrees dynamic model of the single disk rotor system with oil leakage condition is established. By means of the analysis of system kinetic energy, potential energy and oil damping energy, the dynamic equation of system is obtained by Lagrange equation.(4) Based on numerical analysis, the dynamic response of rotor system is analyzed under non-oil condition and oil leakage condition, specifically including the influent of rotating speed, liquid volume and support form to the vibration response of the rotor system.The research of oil shape indicates that, eccentricity has a great influence on the rotating shape of oil. When the rotating shape is eccentric, oil aggregation effect will appear, while, when the rotating axis rotates along the ideal center line, the leakage oil will evenly distributed in the inner wall of the rotating disk eventually. Dynamics characteristics research shows that the existence of oil has significant influence on vibration response of system, specified rotating speed, fluid volume and support conditions of the oil leakage rotor system, will trigger a resonant frequency locking phenomenon of the system, which results in huge vibration amplitude and other abnormal vibrations.