| Based on the background of Beijing South-to-North Water Transfer Project,a one-dimensional unsteady flow mathematical model of long-distance water transfer system with complex inner boundary is established for the long-distance water transfer project.Firstly,based on Saint Venant’s equation,this paper adopts the Preissmann narrow slit method to unify the two types of equations of open channel flow and pressurized pipe flow in mathematical form,and uses the staggered grid semi implicit discretization method to discretize the unsteady flow model equation,in which the first-order upwind scheme is used to discretize the convection term of the equation of motion to increase the stability of the model,When calculating,you can choose a larger Krona number to improve the calculation efficiency.The water hammer equation is discretized by the crank Nicolson implicit scheme for the time center difference.The calculation accuracy can reach the second-order accuracy and is unconditionally stable.The Beijing South-to-North Water Transfer Project has been operated for more than ten years,but there are still some deficiencies.In order to solve the existing problems,this paper uses the hydroinfo hydraulic information system to establish a hydrodynamic model for the multi-source joint dispatching operation of the Beijing South-to-North Water Transfer Project Based on the overall layout of the Beijing South-to-North Water Transfer trunk line project and supporting projects in 2035.In addition,the simulation calculation is carried out for the actual operation transition process of the Beijing section of the South-to-North Water Transfer Project during the 8 months(5760 hours)of the first phase operation phase.Through the comparison of the measured and calculated values for the flow and water level,it is shown that the results fit well,and the following schemes can be calculated to determine the model parameters.This model is used to calculate the different water inflow schemes of the east line and the middle line The dispatching scheme under the conditions of engineering maintenance conditions and engineering accident conditions,and analyze its hydraulic characteristics,put forward reasonable suggestions for unreasonable dispatching operation and water supply scheme,and optimize the project layout and project scale. |
