Research On Key Technology Of Pelton Turbine Runner Design And Manufacture

Hydropower energy industry takes an important part in the national strategic emerging industry development planning, the key part of Pelton turbine unit which is bucket runner, whose design and whole NC machining technology are still not perfect in domestic. Design and manufacturing problems of the bucket runner faced include: how to realize whole NC machining of bucket under the promising of ensuring bucket's hydraulic characteristics; how to predict milling stability for bucket in order to optimizethe milling parameters(length to diameter ratio has exceeded 1:20); how to slovethe vibration problem of overextended hilt during milling impoving processing efficiency and qulity; the problem mentionedabove has restrained key issues of bucket machining technology. This project aims to carry out the following research.Firstly, in order to optimize the structure of bucket for maching, aiming at the interaction between bucket type line and jet flow, based on the CFD(Computational Fluid Dynamics) techniques, hydraulic performance of a bucketis optimizedusing numerical simulation analysis. At the same time, bucket type surface, curvature of uniformity of bucket root, structural optimization design of bucket root's depth and thinkness are researched under machining requests, to satisfy the hydraulic performance and strength characteristics, at the same time, satisfy the NC maching technology request.Secondly, the milling force model of plunge milling process is determined to forcast themilling force. Establishing the FEM of plunge milling model based on the finite element Deform3 D, to analyze effect on the milling force and milling temperature of the amount of feed per tooth, and verified by experiment. In order to restrain the vibration during milling process, stability zone of milling is forcasted with milling dynamics model, influence law of milling parameters on the process stability is relized.Thirdly, according to the analysis of bucket structure and processing technology, to restrain the vibration during machining process, analysical model of hilt vibrationg is established, using the finite element to research geometry of hilt and inner hole diameter parameters effect on hilt deformation and vibration, and verified by experiment. Thus, theoretical basis and reference significance are provided by researching the hilt geometry and the diameter of the inner hole parameters.Fourthly, considering the priority of machining effiency, the CN machining zone of bucket is planned by analysical calculating the of milling thinkness of bucket. The key technology of whole machining process is researched aiming at bucket of Pelton turbine, resolving the problem, bisis is provided to optimize the whole bucket of CN machining process.Considering the key issue of the runner design and manufacture, the new thchnology is obtained with independent intellectual property rights, integrating the research achievement, providing theoretical guidance and practical technical support for the runner of turbine units of whole NC machining in China.