Experimental Study On Physical Leakage Model Of Urban Water Supply Network

With the acceleration of urbanization,the demand for water resources is increasing and the contradiction between supply and demand is gradually worsening.The problem of water shortage has become particularly prominent,thus leakage control in water supply system has become an urgent task.Known as the basis for leakage control,leak model has been a hotspot of research so far.Researches on leak model of water supply system are basically on computer simulation and combined with some conclusions from individual pipe experiments.Few researches have been carried out on water supply network,thus conclusions obtained are often weak in relation to the physical properties of the leakage points.As a result,it is difficult to infer the leakage status from pressure and leakage flow data.Based on leakage experiments of individual pipe,single leak point network and multi leak points network,this paper studies the leakage flow-pressure model of water supply system,and summarizes the direct relationship between the physical properties of leak points and the leak model.In experiments of individual pipe,leakage points of different sizes,different shapes(hole,circumferential break,longitudinal break)and different materials(PPR,PE,UPVC)were studied and exponential leakage models of each leakage points were formed.By summarizing and analyzing the parameters,coefficients were directly proportional to the area,and the ratios depended on its material and shape.The indexes were independent of the area but determined by its material and shape.In experiments of single leak point network,the applicability of the individual pipe’s results was verified,which proves that it is feasible to analyze the connection between the network leakage model and the individual pipe model.Than network leakage models(use average network pressure)under the influence of each leak points were formed and the calculation formulas of the model parameters were fitted.by comparing and analyzing the two kinds of models’ parameters,the relationship between them is established,thus the conclusions of individual pipe experiments could be used in water supply networks.In experiments of multi leak points network,influences of the leak points number were also tested,and through comparing models from individual pipe experiments,the calculation method of model parameters was formed.Network leakage models selecting pressure at network inlet,most unfavorable node and maximum water consumption node were compared with models selecting average network pressure.The results showed that for model using network inlet pressure,the coefficients were scaled down but the indexes were unstable,for model using most-unfavorable node pressure,the indexes were scaled down but the coefficients were unstable,for model using maximum water consumption node pressure,the indexes were scaled up but the coefficients were unstable.Therefore,the selection of pressure influenced the network leakage model,but its accurate parameters could be estimated by the three models selecting different pressure,which could provide the basis for quantifying leakage in water supply network.