Research On Retrofit Technique Of Hydraulic Turbine Based On Numerical Test

A large numbers of hydro turbines among the hydro-power stations that are constructed 20 years ago, are lower in performance index, poorer in manufacturing quality and unreasonable selecting design due to technical restriction, or worsen performance caused by abrasion after a long operating period. It threatens to safety and economic operation for hydro-generation sets and hydro-power stations, so that is an urgent work to upgrade and retrofit lots of hydraulic turbines.It is an urgent task that how to make use of modern technique advance R&D of hydraulic turbine's retrofit techniques, improve the reliability of design, decrease the cost of research and shorten the retrofit period. To meet the practical demand of hydraulic turbine retrofit engineering, this dissertation presents an approach for designing the retrofit scheme according to requirements and restriction of flow passage's retrofit, and try to explore a new approach based on numerical test which can replace the model test of traditional way for retrofit of hydraulic turbine. Then, the computational method which is suitable for numerical simulation of 3D viscous flow of whole passage and efficiency estimation for the preliminary study of hydraulic turbine retrofit project is studied under a preliminary Numerical Test Stand that is consist of commercial CFD software (Fluent) and commercial CAD software (Unigraphics CAD/CAM/CAE).The developed Numerical Test techniques have been applied in the preliminary study of hydraulic turbine retrofit project of YINGXIUWAN hydropower station located in Sichuan province. In this case, according to the practical operating condition and constraints of the original flow passages, anew design goal of runner is suggested for improving the hydraulic efficiency of full operating ranges by lowering the optimum unit discharge. After qualitative analysis, Two upgrading schemes are made on the basis of re-design for 'ErTan' turbine's runner that is one of the best turbines in China.,one is (D to upgrade the runner only and the other is (2) to upgrade the guide vanes and runner simultaneously. According to the possible operating range of YingXiuWan power plant, 14 typical operating points are analyzed by using the whole flow passage's 3D viscous flow numerical simulation and efficiency predication for the two schemes respectively. After numerical simulation and analysis of flow, the two schemes are verified to be feasible. After analyzing the flow characteristic and match between the retrofitted runner and guide vanes and retrofit components of hydraulic turbine, the plan of upgrading the guide vanes and runner simultaneously is considered to be the optimal plan after taking the actual operating range and the related technical-economic indices into consideration. Furthermore, the problems that should be emphasized during the upgrading design are put forward. This research is the basis of reasonable design in retrofitting of hydro turbines of YingXiuWan power plant, which can be as guide for target-making of the upgrading design.It demonstrated that is an effective approach for replacing model test with the numerical test during preliminary study of hydraulic turbine retrofit project, which can optimize design from alternative schemes and reduce the cost of R&D and shorten the period of R&D. It will bring a great technical and economic benefit for hydro-power industry.