Effect Of Simulation Method Of Cushion Layer On Underground Powerhouse Structure Of Hydropower Station

Energy is an important material basis for social and economic development. In China we have rich hydropower resources but most of them have not been developed, so it is important to accelerate the development and utilization of the rich hydropower resources of China to realize the harmony development. With the fast development of hydropower construction, the capacity of hydropower stations is growing in a large scale, and so are the pressure pipes and spiral diameter, and the hydraulic head is growing too, and then the new questions such as the choice, the manufacture, the installment of the diffuser bury way, and a series of questions such as stiffness and stability operation. Although there is a great many of analysis of the experimental study of cushion diffuser structure in China, there are still some questions. Such as the particularity of the stress state under the different cushion plies, the quantitative difference of support structure stiffness and the dynamic characteristics of plant structure, the reasonable choice of cushion laying range and quantity, the design ways of cushion diffuser structure and the adoption of material, all these questions have not been resolved. The core question that the cushion diffuser structure affecting the motion stability has not been resolved which needs the further study. For these questions, the text applies the ANS YS software, built the finite element model of the actual engineering structures underground powerhouse, by analyzing the underground powerhouse structural support stiffness and the dynamic characteristics adopting the cushion diffuser, began the following research and obtained the meaningful research results.(1) Take some giant hydropower station underground work shop for example, we take a middle one standard unit to built the three-dimensional finite element model of the plant overall structure including the cushion diffuser. We analysis the actual vibration by adoption of different form of the cushion unit, bedding materials, compressive modulus and the scope of cushion laying, and compared the affection of the overall structure of the natural frequencies, on the purpose of supply some reference to the natural vibration of the workshop structure.(2) We analysis the hydroelectric generating set support structure-the stiffness of the structure of the machine pier and seat ring by the numerical simulation method and get the weakness degree of the machine pier in the stator base and the lower rack of basic horizontal and vertical stiffness and seat ring structure radial stiffness for different cushion analog mod and to supply some reference for the design of volute bedding structure of large hydropower plant.(3) To study the affect of the structural dynamic characteristics of cushion volute of the different cushion parameters, which were built on the linear and nonlinear finite element model, using time history analysis method and analysis of the effect of dynamic response of steel spiral case and its concrete structure surrounding of cushion material nonlinear under the pressure pulsation in the turbine runner, hoping to increase the optional facts to the choice of the volute cushion parameters from the aspect of nonlinear dynamic.