Analysis On The Strength Of Flow Passage Components And Fatigue Life Of The Vane Of Tubular Turbine

China has abundant water resources and the proportion of hydropower accounted for national energy is also increasing constantly. At present, most of the high head resources have been developed, leading to the large number of use of bulb tubular water turbine as a low-head hydropower generating equipment. Due to the instability and changing operating conditions and other factors of the flow, the turbine will produce complex stress and vibration, so that many hydropower units produce varying degrees of damage. Therefore, the stiffness and strength and the dynamic characteristics analysis on the main flow passage components of turbine is very meaningful for improving the hydraulic performance of the turbine and increasing the stability of the unit.The finite element analysis technology is mainly used in this paper. Basing on introducing the analysis situation of water unit at home and abroad and bulb tubular turbine units and parameters, it describes the basic principles and steps of the analysis using the finite element method. The tubular seats as the main support parts and blades undertaking the conversion of hydropower to mechanical energy will be the research emphasis. Through using the UG software for the flow passage components to model, it divides the structure into grids by Hypermesh software, the establishing a finite element model. Then put the finite element model into Ansys software for finite element analysis, we will get the results of the stiffness and strength analysis and dynamic stress analysis of the structure. Analysis obtains the maximum displacement and stress concentration region of the structure under different conditions, find the stress concentration point. In the water turbines operating process, water flow state is changing constantly as well as water pressure, so that this paper calculated the response of the structure to the hydrodynamic pressure according to pressure variation and obtained the changing process of maximum structural stress over time, providing reference for optimization structure. In order to study the nonlinear characteristics of the flow components, this article still analyzes the stiffness and strength and dynamic stress of the structure under nonlinear conditions on the basis of linear analysis. Around the blade can produce exciting force because of the instability flow, and the force will lead to crack at the blade runner, it makes fatigue life prediction analysis on the blade according to the results of the analysis of the dynamic stress, predicting the time of the blade cracks and providing time basis for the power plant maintenance.Through this research, we draw the strength properties and the dynamic stress characteristics of the main flow passage components of bulb tubular turbine, and predict the time of the runner blade cracking. The results of this study provide optimized basis to optimize the structure for structural designers, as well as time basis of the maintenance on the unit shutting down for the power station staff.