| Water resources of our country are very rich,which mainly concentrated in the western,and have characterizes such as high head drop and more sediment.Under this circumstances that the speed,capacity and head are math each other,and compared to impulse water turbine Francis turbine has been recognized universally by have many advantages that great efforts especially complex cascade of runner,stable operation,a good anti-abrasion performance,high-efficiency,and so on.In order to make a valuable and renewable clean energy been fully developed and utilized,in this paper,for the 125-meter head of water resources,to develop a new performance of the turbine composite wheel hydraulic model program.With the support of the Computer-aided design(CAD) and the CFD computational fluid dynamics numerical techniques,do research and explore to the complex runner internal flow.In order to find out the short blade airfoil and the layout of the location within the whole flow field of the law of mobility and performance,and improve the short blade and the runner design method.Have high academic value and practical significance to important projects,and if successful,then the prospects for broad application.The author selected a better performance runner as the initial program in the paragraph applicable to the head of the conventional turbine.According to the design parameters,select the type of runner HL153-600 model as the initial wheel,to be developed the HL153-640 turbine complex wheel hydraulic model program.The main results of research and creativity are as follows:1.Based on similar principles of turbine design parameters and requirements,design a good long complex blade.Based on the long blade wood-mode design the short blade and the blade lattice,in this paper,corresponds to the horizontal cross-section long blade's working surface as short blade working surface,proportional scaling along with horizontal cross-section and the long blade.With PROE/E powerful entities and editing function, rapid generate the 3D solid model of short blade.By Pro/E surface analysis,basically,the face and back can achieve smoothness requirements,and be used as the short blades base model.2.For wheel hydraulic design with parameters that the number of long blade and short blade,the degree of bias to short blade,and the length ratio the long blade and short blade. Maintain the same position for the short blade and long blade,not consider other radial bias,and improvement design of multi-program,to the entire flow field including volute and draft tube,doing numerical simulation.For one design,using different turbulence model,grid number and the iterative residual,and as much as possible minimize the scope of artificial error,to ensure the late results stability and accuracy.By numerical analysis predicting the performance curve,has the impact trend for turbine performance when add short blade lattice:η-H curve more smooth,and wider efficient area; Q-H curve shift to the large flow direction;N-H curve more steep.3.Volute,guide vane and draft tube are important flow components to turbine.For deficiencies that turbine full spiral type spiral case conventional methods of hydraulic design have,using numerical method, follow the movement of water that the speed moment is a constant,Without having to convert the elliptical cross-section,in order to improve the non-circular cross-section of the volute design method of hydraulic.By the flow field simulation analysis to verify that the design volute not only flow with the design of basic assumptions,and flow field distribution can meet with its theoretical analysis,but also the design flow smooth,and good flow distribution. Hydraulic model study and development in this project is a new model, because of the limits of time and conditions and my lack of experience,there are a lot of work not done well.Its doesn't satisfied that the Hydraulic model in this paper,and technical performance indicators are not enough advanced too.There has further room for further study in the future.
|
PDF Full Text Request