Strength Analysis And Optimization Of Main Shaft Of Bulb Tublar Turbine-Generator

Turbine-Generator machine set is the crucial equipment of waterpower. Bulb Tubular Turbine-Generator is the eximious type that develops the hydraulic resources of low headwater. With the development of the national economy of our country, among the hydraulic resources that can be developed in economic developed coastal area and plain area, power stations of high and middle headwater have been developed completely step by step. To meet the demand of power with fast economic development, the development of the hydraulic resources of low headwater has been taken into account. It is benefit to improve the level of designing this type and production efficiency if the thought of Finite Elements Method and Optimization Design combined with engineering analysis software is applied into development and design of Bulb Tubular Turbine-Generator.In this paper, main shaft, one of the key parts of Bulb Tubular Turbine-Generator, is analyzed with Finite Elements Method and the Theory of Optimized Analysis combined with Pro/e and ANSYS, mainly static strength analysis and optimized design analysis.Firstly, according to the actual structure of main shaft, three dimensions substance geometry model is built with Pro/e, and the relative small structures are neglected to predigest the model. According to the request of Finite Element, Analysis, I modified the model, and neglect the holes on flanges. Then the solid geometry model is entered into ANSYS to do the pre-treatment of FEA. It is disassembled by ten-noded tetrahedron elements.Secondly, static strength of main shaft is analyzed and calculated with ANSYS to gain the stress distribution and deformed state of main shaft. Analysis result shows: the stress on the part of transition from flange to shaft body is greater and more complex;by contrast with material submitted stress limit, strength reserve of main shaft is still greater. In a word, main shaft meets the requirement under various static loads.Finally, the result of stress distribution and deformed state of main shaft shows: The maximal stress value in original design is much less than the breaking point of material. So it is necessary to optimize the structure of the main shaft. The model of optimized analysis is founded with parameter. Then the model is optimized analysis after the establishment of design variable and design object and so on. The result of optimized analysis shows: The stress and strain of main shaft distributed more reasonably. The material is sufficiently used, the weight effectively lightened. So the cost of product is reduced.The research for main shaft has lai'd certain foundation for analysis with FEM and optimization design of overall machinery and others parts and calculation of vibration responds. The research play the guiding significance role in applying ANSYS into other parts of waterpower equipment.