Water Supply Pipe Network Drop-Restore Pressure Leakage Control Based On Viscoelastic Theory

As one of the world’s major economic powers,about one-quarter of the provinces are areas where water resources are seriously lacking.The issue of water resources has always been an urgent problem for China.Not only does our citizens need to have the awareness of water conservation;from the water supply yearbook,the average total leakage in recent years has reached 6.1 billion m~3,and we need to reduce the amount of water consumed by leakage reduction measures.At present,water supply enterprises mainly reduce leakage through passive leakage,leak detection and pipeline modification.However,the results are not satisfactory,and the goal of controlling leakage is difficult to achieve.In order to minimize the loss,the pressure management of the water supply network has been paid attention to.Pressure management is widely considered as an important means to control the leakage of the water supply system.The pressure management method can reduce the energy consumption,reduce the rate of pipe burst,and crack the pipe network.The development has a certain preventive effect.The traditional pressure management considers that the leakage and pressure are completely positively correlated,ignoring the influence of pressure operation mode,and the plastic pipe is widely used,lacking effective mechanism research.In this paper,the mechanism of the phenomenon that the leakage and the water supply pressure have been found in the laboratory is not a simple positive correlation.The mechanism of this phenomenon is studied.The viscoelastic theory is used to explain this phenomenon reasonably and based on the hysteresis of viscoelastic properties.The effect,the method of drop-recompression loss control is proposed,and the traditional leakage-pressure relationship is corrected.The loss is not only related to the instantaneous pressure,but also related to the historical pressure.According to the Boltzmann superposition principle and the generalized Vogt-Kelvin model,the viscoelastic leakage model is constructed to quantitatively describe the leakage and pressure relationship of the polymer pipe.The pressure-driven analysis method is studied,and the non-iterative pressure-driven node flow model is established.The effectiveness of the method is verified in the example pipe network,and the constructed viscoelastic leakage model is embedded in it.A pressure-driven viscoelastic leakage model is established.The model can not only simulate the shortage of pipeline pressure and accidents,but also consider the leakage,and more accurately simulate the actual operation of the pipeline network.In order to verify the effectiveness of the drop-reduction leakage control and the accuracy of the pressure-driven viscoelastic leakage model,a southern district Y was selected as the experimental plot.As the community Y is close to the factory water,the pressure of the whole water supply pipe network is in a high state,and it is controlled by the down-recompression operation on the working day.The leakage rate is reduced from 37.7%to 16.8%,and the estimated monthly water saving amount is 2760m3.Water supply enterprises can save about 100,000 yuan a year and can achieve better benefits.It can be concluded that when the water supply pipe network has a large pressure reduction space,in order to minimize the leakage,a down-recompression operation can be added in the conventional pressure reducing operation,and the leakage reduction can be achieved without changing the operating conditions.The effect,which also provides data support for the application of the drop-recompression loss control to the actual project.