Leakage control of water distribution system by drop-restore pressure based on viscoelastic mechanism

Abstract

[EN] As a common method to control leakage of water distribution system, pressure management has the advantages of reducing energy consumption, reducing the possibility of explosion and avoiding the aggravation of leakage. In recent years, with the popularization of plastic pipe in the world, it is necessary to study its leakage characteristic. Our research group carried out leakage experiments on high density polyethylene (HDPE) pipe, and found that the correlation curve between leakage flow and pressure did not completely coincide in the phase of pressure boost and pressure reduction. The existing FAVAD and exponential leakage models could not explain this phenomenon, which challenges the pressure management theory dominated by a single depressing-pressure process, thus it’s necessary to explore pressure management strategies suitable for plastic pipes. Based on the viscoelastic properties of plastic pipe, we established the viscoelastic leakage model and proposed the leakage control method of drop-restore pressure, and verified its feasibility in practical engineering case. The main research objectives of this paper will be firstly to describe the strain response of leakage area in the process of continuous stress application with the Boltzmann superposition principle for HDPE pipe; the Voigt-Kelvin model is used to simulate the creep behavior of viscoelastic material, and a suitable leakage model for viscoelastic pipe is proposed to provide accurate expression of the leakage under the regulation of drop-restore pressure. Secondly, the viscoelastic pipe leakage model is embedded into the pressure-driven analysis model based on non-iterative method, and the pressure-driven viscoelastic leakage model is obtained. Finally, evaluating the proposed leakage model in the practical case. With the minimum of leakage flow as the objective function, the leakage control model of drop-restore pressure is established and solved by particle swarm optimization algorithm to obtain the accurate pressure regulation scheme. After applying the scheme from the optimization, the leakage rate decreases from 37.7% to 16.8% on weekday, which is great impact on leakage control.