Multidisciplinary Optimization Design Of Spliters Of Francis Turbine With High Water Head

The runner is the key part of the hydraulic power unit and is the most vulnerable part in hydropower operation. The new runner needs to improve the efficiency of cavitation, abrasion and stress concentration as far as possible to improve the overall performance and achieve the safe and economical operation index of the unit. The runner with spliters has the advantages of wide range, small vibration and cavitation erosion resistance, and the development foreground is broad.Hydraulic and structural performances are two main subjects in the optimization design of hydraulic machines. This article gives consideration to both hydraulic and structural performances during the optimization process of hydraulic turbine with long and short blades on the basis of Multidisciplinary Optimization Design (MDO). The aim is to improve the optimization methods of hydraulic turbine, shorten the development cycle time and ensure stable and efficient operation of the unit. CFD and FEM analysis are combined to improve the overall performance of runner in the multidisciplinary optimization process of high head Francis turbine runner blades. This optimization considers the whole runner including the crown and band to get more accurate results of stress distribution.The use of the UG Open Grip Language makes the parameterization of blades come ture.Bezier curve is used to fit the bone line and it changes the blades through transforming the bone lines of different sections. The optimization variables are mean line shape, offsets in the head of aerofoil and relative thickness. The objective functions of optimization are the efficiency, the lowest static pressure of blades and the maximum stress of runner. The constraint condition is th,e head.The multidisciplinary coupling information is transformed and analyzed. NSGA-?algorithm is adopted for optimization calculation.The runner are optimized in three operating conditions respectively. Super-transitive approximate is used to weigh three conditions and the final optimization result is the large flow rate obtained by comparing these optimization results of different geometries. The optimizedrunner efficiency is improved, the lowest static pressure is promoted, and the maximum static stress is decreased. The whole performance of runner gets improved and it provides a feasible method for engineering application in the multidisciplinary optimization design of spliter.