Change The Shape Of An Elbow Draft Tube Back To The Energy Coefficient

Tube unit is to achieve an important component of energy recovery, the overall energy of the turbine unit has great features and stable operation of the impact of the performance of its draft tube geometry is closely related to the shape. Tube well designed, uniform and stable internal flow, secondary flow is not serious, the loss is small, back to factor high. The design is not good, may make it appear larger internal flow back and bend at the convection, resulting in increased vibration of the draft tube, the unit operating in an unstable state.In this thesis, generating complete sets of equipment Co., Ltd. Ganzhou, in the practical application of the draft tube back to the actual encountered the problem of poor coefficient, using Fluent commercial software, based on the Reynolds time-averaged NS equations and the standard equation to a hydropower Francis Tube turbine unit model as an example, the analysis of the theoretical knowledge and research, focuses on resistance loss and the end of the pipe back to the relationship between coefficient derived back to the end of the pipe and the diffusion coefficient of the relationship between the angle and Improvement of this optimization program accordingly.For the previous theoretical analysis and research, application software Fluent tube for the numerical simulation. Gambit software through improved draft tube is modeled using Fluent commercial software after the original tube and improved compared to simulation, calculation and export a number of simulation data and charts, and thus further analysis of the speed of the draft tube Field, pressure field. And under different traffic conditions and improved the original condition of the tube, again cross-section velocity and pressure field analysis and comparison.Finally some simulation software by Fluent export data and forms a comprehensive analysis, the results show that the new improved design of the tail pipe end can be a good solution to part of the water in the practical application problems, to strengthen the draft tube Practical problems in energy recovery, and its analysis of the results and tables for future improvement of the tail pipe and the reference design provides the basis for the development of the draft tube and the study of the more important scientific significance.