Elasto-plastic Analysis Of The Rotor And Wedges Of 1000MW Supercritical Turbogenerator

Turbogenerator rotor and wedges are very important parts of the turbogenerator. the strength design of rotor and wedges will directly affect the stability and security of the whole machine. With the development of supercritical and ultra-supercritical turbogenerator, higher demand to the material properties and structural design of rotor is put forward. In normal running conditions, the rotor bear own centrifugal force caused by high speed rotation, bending stress caused by gravity and pressure from wedges. Rotor has a lot of grooves and transition chamfers, so its stress distribution is very complex. The strength of rotor and wedges should be analysed in order to ensure the normal operation of generator.In this paper, finite element analysis of the model of rotor and wedges is made by ABAQUS software. The main research work and results are as follows:1. The development of supercritical turbine-generator is described in detail. Research aims and significance, research status at home and abroad, and methodology are demonstrated. The basic principle of finite element analysis is explained, and its application in strength analysis of rotor and wedge is studied. Analysis process of rotor and wedges is determined.2. The finite element model of rotor and wedges is made by ABAQUS software. Strength analysis of rotor and wedges is completed successfully in different working condition, and stress distribution of rotor and wedges is gained, then the stress of all dangerous points is checked. The structure of rotor and wedges has a total of three dangerous points which do not meet the demand of strength design. These three points are located at tooth root chamfer of rotor which match with aluminum wedges, shoulder end chamfer of aluminum wedges, and co-groove chamfer of rotor which match with non-magnetic steel wedges.3. Tensile test of rotor material is completed in order to obtain the elasto-plastic constitutive relation of rotor material. Solving method of elasto-plastic model of rotor and wedges is given. Elasto-plastic analysis of the finite element model of rotor and wedges is completed successfully. Thereupon, the structure's real stress distribution, plastic deformation region, and maximum plastic strain are achieved. By comparing maximum stress and plastic strain regions in different parts of the rotor, one conclusion is made that the smaller the chamfering radius of the rotor is, the larger the stress gradient is.4. The rotor has two dangerous points. This paper reconstruct the model by selecting severe different chamfering radius to every dangerous point on rotor and analyse the stress condition of every model. The results show that stress concentration degree is under the influence of transition chamfering radius. The bigger the chamfering radius of rotor tooth root is, the lower the maximum stress of rotor tooth root is. The bigger the chamfering radius of rotor co-groove is, the lower the maximum stress of rotor co-groove is.5. By analyzing all the force to wedge, one conclusion is made that wedge angle has nothing to do with average pressure of wedge shoulder. Different models are made by selecting different wedge angle. The stress conditions of these models show that wedge angle has no influence to the maximum stress of wedge. Software analysis results verify the theoretical analyses.6. Different models are made by selecting different chamfering radius of wedge shoulder end. The analysis results showed that the smaller the chamfering radius is, the higher the maximum stress of wedge is.In this paper, based on finite element analysis of rotor and wedges, stress distributions in different working conditions is obtained, and design scheme of rotor and wedges is put forward. It has important realistic guarding significance.Multi-iterations are essential in order to analyse Elasto-plastic problems and contact problems, especially for rotor with huge shape and complex structure. It is hoped that this paper can make contributions to further research on Elasto-plastic problems and contact problems, and offer some insights into these non-liner problems.