Hydraulic Model Exploitation And Study Of Medium-high Head Francis Composite Runners

Hydropower resources in the composition of the position in China's energy is very important,It is a quality of energy and already can regenerate and don't pollute the environment. According to the survey,China's hydropower resources in the world is NO.1,but its development level is lower.Hydropower resources development and utilization has broad prospects.Using the hydraulic turbine is the key equipment of using resources.In a variety of types of turbine,Francis turbine is the most widely used in a pattern because of its simple structure,using head range and efficient area wide,the application is wide in the hydropower both at home and abroad.Turbine runner is the key components,It directly convert from water flow energy to rotating mechanical energy.Wether the good design of tuebine runner or not affects conveyance capacity,hydraulic efficiencies,cavitation characteristics,work stability and adaptability of variable.At the same time,it influences the whole machine set and the full use of water.Based on the hydraulic resources in west China the characteristic of the large gap,a new excellent performance of the turbine compound runner specific to the head of 150m-180m is exploited. Further more reasonable,full and effective use of hydropower resources,The resource advantage is made into economic benefit and social benefit.1.According to the existing hydraulic model runner full-port geometric parameters similar to the head and the specific speed, using the Dualistic Theoryω=0,in accordance with the request that runner have the highest speed and conveyance capacity, the higher maximum efficiency and average efficiency, the good cavitations performance, stability and the adaptability for changing work condition etc. The airfoil of thelong blade and the conventional runner(only contains the long blade) is designed, and is optimized by CFD simulation.2.The short blade is based on the designed long blade and made by the software Pro/E.3. The spiral case,the draft tube and others are making hydraulic design and three-dimensional modeling.According to the shortcoming of the conventional hydraulic design,the spiral case corresponds to woking principles by numerical calculation in order to improve the hydraulic design of non-circularsection of the spiral case.4.For the runner hydraulic design with parameters that the number of long blade and short blade, the degree of bias to short blade,and the length ratio of the long blade and short blade. Maintain the same radial position for the short blade and long blade, and improve design of multi-program, and make numerical simulation of the entire flow field including the spiral case and the draft tube.Through the analysis of numerical simulation, the best combination will be obtained.5.The turbine of the best combination of the number of long blade and short blade, the degree of bias to short blade,and the length ratio of the long blade and short blade predict performance.Based on the CFD simulation 25 different conditions, the working characteristic curve of the turbine draw. From the CFD analysis estimated performance table and the working characteristics curve, the highest efficiency is 93.38%,main points is above 90% of efficiency,basically achieved francis turbine runner energy requirements. Through the numerical simulation on the large flow condition, design, small flow condition,the internal flow is given.The results show that the pressure, velocity distribution of the design condition is best, and the other is to meet the expected require.