Vibration Analysis On The Rotor System With Seal

Rotor system is an important part of large rotating machinery (such as the generator set, hydroelectric generating set, nuclear power generating units, air aerospace engines and industrial compressors, etc.). Gas dynamic excitation is a main factor to threat the rotating machinery safety. Labyrinth seal is widely used as an effective gas seal, which mainly used for turbine stage, at the top of the leaves, the cooling flow path system, gas separation and oil and gas isolation in seal system of main bearing oil chamber. It is difficult to avoid biasing in a sealed cavity, once it happens, Seal excitation force will appear because of the uneven pressure. The disturbance and sealing of the rotor flow interacts with each other, sealing excitation force is characteristics. In certain conditions, the rotor system can be excited by labyrinth seal force, which will cause the self-excited vibration of the rotor system.This paper mainly studies the rotor system vibration problems caused by gas seal force. At first, the rotor system dynamics equations with Muszynska seal model was established, using numerical calculation method to simulate the system vibration. Secondly, the influence of gyro effect on the rotor system with sealing force was analyzed. Thirdly, the shaft vibration was analyzed by use of finite element method. Finally, the rotor system dynamic characteristics of asymmetric elastic support with sealing force were analyzed. Main contents are as follows:(1) The rotor system with seal structure of was simplified, introducing Muszynska seal model, the rotor system dynamics model and its dynamic equation considering the quality of bearing were established.(2) Numerical simulation of the rotor system vibration with Muszynska seal force response was done by use of the fourth-order Runge-Kutta method. The frequency domain chart, axis path chart and the Poincare sections chart were gotten. And the vibration characteristics of rotor system under the imbalance of excitation force and sealing force in different speed was researched. Numerical simulations show that the rotor system will appear period, quasi-period, chaos vibration.(3) The influence of gyro effect on the rotor system dynamic characteristics was analyzed. (4) Based on the finite element method, the vibration response of the axis of the rotor system with seal was analyzed.(5) The rotor system dynamic characteristics of asymmetric elastic support with sealing force were analyzed.This work has the vital significance on the vibration analysis of rotor system with the gas seal structure.