Study On Hydraulic Stability Performance Optimization Of Large Scale Kaplan Turbine

The clean hydraulic power is fully developed with priority in the world.With the development of the times,the turbine scale and output are increasing,and the turbine stability is more important to be considered for the turbine safety operation.The domestic largest scale Kaplan runner of the Hongshi power plant is designed and manufactured in the eighties,after the operation for many years,the turbine stability of the serious problems is focused,and the turbine is proposed to be optimized with the current design.In this thesis,based on the runner promotion project of the Hongshi power plant,the hydraulic stability of the Kaplan runner is systematically discussed and the promotion result is provided.The parameters of the blade inlet angle,blade outlet angle,blade thickness and blade angle are optimized with the result of the original runner A1,the pressure pulsation is emphatically considered besides the efficiency and cavitation characteristics.During the optimization research process,three runners are designed for the A2,A3 and A4,the blade flow separation on the suction side is emphatically optimized to achieve the expected result.During the research process,the model turbine test is conducted on the hydraulic test stand with the efficiency test,cavitation test,pressure pulsation test,flow view observation,etc.The test results show that optimization efficiency are improved,the pressure pulsation and blade flow separation are improved especially.After the optimized turbine runner operation,the A4 prototype test is conducted.With the comparison of the prototype confirmation test result,the cross flow of the optimized A4 is more stable than the A1 prototype runner,and the stability characteristic is improved.Because of the inherent Kaplan limitation,it is unpractical to greatly reduce the pressure pulsation after the promotion.It is correct and feasible to reduce the flow separation which causes the high frequency alternating stress on the blade for improving the stability characteristic.The flow separation is reduced that shows hydraulic research method is correct and the promotion result is successful,the methods and ideas,which is the cooperation of the three hydraulic research methods with the hydraulic calculation,model test and prototype test,are provided for reference for the same optimization research in the future.