Leakage Analysis And Pressure Control Research Based On Nocturnal Minimum Flow Method

In recent years,due to the accelerated development of urbanization,in order to better meet the needs of residents and enterprises for water,the volume of urban water supply and the pressure of the pipe network has gradually increased.However,with the aging of the pipe network and the dysfunction of the pressure control of the pipe network,pipe bursting accidents and leakage rate are frequent,which have seriously affected the production and life of the people.In the current stage of urbanization,how to predict and reduce the leakage of water supply network has become a hot research content.This paper mainly focuses on four aspects of leakage assessment and analysis,research on leakage analysis method based on night flow,prediction of new leakage,and pressure-based leakage control,including:(1)The main causes of network leakage are briefly described,and the actual network leakage is analyzed using the "top-down leakage assessment" method and the "bottom-up leakage assessment" method,respectively,with the example of a pipe network.The results show that both methods have good applicability for network leakage assessment.(2)A nighttime minimum flow model of the water supply network was established to estimate the all-day leakage of the network based on the variation of AZP points.The hydraulic model similar to the actual network is constructed by EPANET software,and the relative error analysis and sensitivity analysis of the leakage amount estimated by AZP method are carried out to explore the application prospects of the method.(3)Two mathematical models for predicting pipe network leakage based on nighttime minimum flow data were developed.Among them,the moving average interval model can reduce the disturbance caused by the fluctuation of water consumption at night,and the determination efficiency is greatly improved,and the optimal moving average days M and the leakage threshold are determined.The normal distribution model uses five confidence levels and compares them with the actual nighttime water use by analyzing the nighttime water use data briefly and at a high frequency,and finally sets the best confidence level at 95.5% to estimate the true leakage amount,thus providing a basis for timely detection of new leakage.(4)By installing real-time control pressure reducing valves to regulate the pressure of the pipeline network,the actual water supply pipeline network in CYN area is selected as the research object,and the optimal control model of pressure reducing valves is established,and the leakage coefficient of the nodes of the pipeline network is solved by combining with the nighttime minimum flow method,and the leakage amount of the pipeline network is finally obtained.The particle swarm optimization algorithm(PSO)and the whale optimization algorithm(WOA)are used to solve the leakage amount as the objective function,and finally obtain the optimal value of the post-valve setting of the pressure reducing valve and compare the convergence speed and accuracy of the two optimization algorithms.The research results show that the method has practical significance for the leakage control of pipeline network.