Research On The Effects Of Labyrinth Seal On The Dynamic Characteristics Of Rotor System

The effects of sealing on high-speed rotating machinery have drawn increasing attention.The labyrinth seal airflow induced force imposing on the rotor has non-negligible influence on the stability of rotor system.So the research on the rotor dynamics behaviours of rotor-seal system will give a reference for its design and fault diagnosis.In this paper,firstly,a numerical method based on commercial software FLUENT is used for simulating flow fields and studying seal performance and dynamic coefficients of straight-through,stepped and staggered labyrinth seals.The effects of rotor speed and pressure difference on leakage and dynamic coefficients are investigated.Then,the labyrinth seal from a third-stage rotor of TRE100 centrifugal air compressor used in a thermal power plant is taken as the object of analysis to calculate its dynamic coefficients in conditions of different seal clearances,pressure differences and rotor speeds.According to the dynamic coefficients,dynamics model of rotor-labyrinth seal system is built by using finite element method.With gyroscopic effect being taken into account,the influences of bearing stiffness,seal clearance,axial location,pressure difference,rotor speed on modal shapes,critical speeds and harmonic response characteristics of rotor-seal system are discussed by using ANSYS.The results have certain significance to structure selection and parameter determination of labyrinth seal.