Research On The Dynamic Characteristics Of Large Steam Turbine Rotor-Brush Seal System

The technical and economic requirements of modern thermal power generation technology promote the sealing technology of high performance turbomachinery.Because the advanced brush seal technology can significantly improve the reliability and efficiency of large thermal power units, the brush seal in power plantis applied more and more widely. But the friction heatgenerated between the shaft and brush seal not only affect the brush, thereby affecting sealing performance and flow field characteristics, but also impact natural vibration characteristics of rotor. Therefore, it is necessary to study the flow characteristics of brush seal and fluid-solid coup ling vibration characteristic of rotor-brush sealing system,and it also reflects the important scientific value and practical significance.This paper first studies the geometry and mechanics relations of single filament and rotor, then gets the force expressions;basing on Thomas eight-parameters model and Taylor expansion formula ,acquiring the model stiffness expressions and deducing easily the applied rotor-brush stiffness model and simulation. This favors third chapter of rotor-brush seals-bearing System modal analysis.This paper introduces the finite element analysis method and equation,and makes a simple introduction of the corresponding mode ling unit, and then the finite element model is established according to the actual 1000MW unit in a power plant. Compared finite element numerical results with the data power provided, this verifies the correctness of the model, which favors prestressed modal analysis for the fifth chapter.This paper study on the flow characteristics of brush-rotor seal system. A numerical analysis model of porous media is built, by using the empirical formula for calculating brush seal viscous resistance coefficient and inertia coefficient. Calculating the brush seal leakage rate of export visa FLUENT and compared with the experimental data in the literature, this indirectly verified the rationality and correctness,then studying the influence of some factors on the flow field and temperature field.This paper study on the rotor-brush seal system fluid-thermal-structural coupling effect on the stress and deformation of the rotor. Based on the analysis of the third chapter, we study on this by adding to temperature load and centrifugal load and thermal stress and centrifugal force influence on the vibration characteristics of rotor.