Time-delay Equations Description Of Hydraulic Units Water Conveyance System's Dynamic Characteristic And Water Hammer Calculation Research

Current methods for hydraulic units' water conveyance system water hammer and Transition Process calculation is mainly numerical method and analytical methods based on pressurized unsteady flow numerical method basic equations. Wherein, C haracteristic Method is representative of numerical method with advantages of complex boundary conditions treat simple, high accuracy, since this method can not provide continuous water pressure and flow expression, it is not conducive to building a continuous hydraulic unit model; Analytic methods is generally based on a simplified form of the water hammer basic equations' Taylor series expansion, provide convenience for the research of hydraulic unit control policy, but this method is too difficult to accurately reflect the dynamic characteristics of the water system. Time-delay differential equations group accurately reflect the essential characteristics of the hydraulic fluid conduit changes, facilitate the establishment of high-precision hydraulic unit model. Therefore, Research of time-delay differential equation methodology for water conveyance system water hammer calculation and the corresponding application of the actual project is necessary.According to the basic principles of water hammer calculation, to study the time-delay equation of general single pipe,the upstream end of the reservoir pipe and the downstream of reservoir pipe;to study nonlinear mathematical model of the impedance surge chamber; given over time-delay differential equations describe of four typical water conveyance system, and then summed up relationships between dimension of time-delay differential equations and the number of various links; shown and illustrates the method for solving time-delay differential equations of the two different kind of water conveyance system; Research on methods of improvement by interpolation difference equations. Establish and improve the method of water conveyance system described by delay differential system.In order to analyze computing performance of the analytic method, C haracteristic Method, time-delay differential equations describe, use a actual hydro-power plant to the study the transient calculation test, the time-delay water conveyance system model has advantages of high computing speed and precision. The feasibility and superiority of the method are verified.Based on the dynamic equations of the pipeline delay equations and impedance surge chamber to study the dynamic characteristics of water pipes and pressure change cycle expression containing impedance surge chamber, and then use a long water conveyance system hydro-power plant as the object of study, to research the influences of impedance pore size and the impedance surge chamber position on the hydraulic performance indicators, on the basis of this, the above two parameters are rationally configured.