scholarly journals Absolute roughness calculation by the friction factor calibration using the Alternative Hydraulic Gradient Iterative Method on water distribution networks

RBRH ◽  
2017 ◽  
Vol 22 (0) ◽  
Author(s):  
Alessandro de Araújo Bezerra ◽  
◽  
Marco Aurélio Holanda de Castro ◽  
Renata Shirley de Andrade Araújo ◽  
Keyword(s):  
Iterative Method ◽  
Friction Factor ◽  
Water Distribution ◽  
Distribution Networks ◽  
Hydraulic Gradient ◽  
Pipe Material ◽  
Pressure Measurements ◽  
Pressure Data ◽  
Universal Equation ◽  
New Formulation

ABSTRACT The main objective of this research is the development of a new formulation for calibration of the head loss universal equation friction factor using the Alternative Hydraulic Gradient Iterative Method for calculating the absolute roughness. The method was applied with the aid of Epanet2.dll library for hydraulic simulations in two fictitious distribution networks. The influence of the initial roughness adopted, the number of nodes with known pressure data and position of the nodes with known pressures was tested. To test the influence of the initial roughness to be adopted a computer subroutine has been developed in order to calculate the most appropriate initial roughness for each section. The results showed that it is recommended to use as starting absolute roughness the usual value for the pipe material as new. The developed computational subroutine is recommended for unknown pipes network material or very old networks. How higher number of known pressures in the distribution network, better the accuracy of the method. However, a good layout of the nodes with known pressures was more important than a large number of pressure measurements. The best configuration found to the nodes with known pressures they were separated compared setting together with each other. The method was simple to apply and with good results, and can be applied with a small number of iterations.

scholarly journals Robust Data-Driven Leak Localization in Water Distribution Networks Using Pressure Measurements and Topological Information

Sensors ◽  
2021 ◽  
Vol 21 (22) ◽  
pp. 7551
Author(s):  
Débora Alves ◽  
Joaquim Blesa ◽  
Eric Duviella ◽  
Lala Rajaoarisoa
Keyword(s):  
Water Distribution ◽  
Pressure Sensors ◽  
Distribution Networks ◽  
Water Distribution Networks ◽  
Data Driven ◽  
Pressure Measurements ◽  
Leak Pressure ◽  
Flow Measurements ◽  
Topological Information ◽  
Probable Path

This article presents a new data-driven method for locating leaks in water distribution networks (WDNs). It is triggered after a leak has been detected in the WDN. The proposed approach is based on the use of inlet pressure and flow measurements, other pressure measurements available at some selected inner nodes of the WDN, and the topological information of the network. A reduced-order model structure is used to calculate non-leak pressure estimations at sensed inner nodes. Residuals are generated using the comparison between these estimations and leak pressure measurements. In a leak scenario, it is possible to determine the relative incidence of a leak in a node by using the network topology and what it means to correlate the probable leaking nodes with the available residual information. Topological information and residual information can be integrated into a likelihood index used to determine the most probable leak node in the WDN at a given instant k or, through applying the Bayes’ rule, in a time horizon. The likelihood index is based on a new incidence factor that considers the most probable path of water from reservoirs to pressure sensors and potential leak nodes. In addition, a pressure sensor validation method based on pressure residuals that allows the detection of sensor faults is proposed.

scholarly journals The Unfavourable Impact of Street Traffic on Water Distribution Pipelines

Water ◽  
2018 ◽  
Vol 10 (8) ◽  
pp. 1086 ◽  
Author(s):  
Ioan Așchilean ◽  
Mihai Iliescu ◽  
Nicolae Ciont ◽  
Ioan Giurca
Keyword(s):  
Cast Iron ◽  
Water Supply ◽  
Water Distribution ◽  
Road Traffic ◽  
Distribution Networks ◽  
Negative Influence ◽  
Supply System ◽  
Water Supply System ◽  
Pipe Material

This article analyses the relation between the failures that occurred in the water supply network and the road traffic in the city of Cluj-Napoca in Romania. The calculations in this case study were made using the Autodesk Robot Structural Analysis Professional 2011 software. In the case study, the following types of pipes were analysed: steel, gray cast iron, ductile cast iron and high density polyethylene (HDPE). While in most studies only a few sections of pipelines, several types of pipelines and certain mounting depths have been analysed, the case study presented analyses the entire water supply system of a city with a population of 324,576 inhabitants, whose water supply system has a length of 479 km. The results of the research are useful in the design phase of water distribution networks, so depending on the type of pipe material, the minimum depth of installation can be indicated, so as to avoid the failure of the pipes due to road traffic. From this perspective, similar studies could also be carried out regarding the negative influence of road traffic on sewerage networks, gas networks and heating networks.

scholarly journals Comparison of four models to rank failure likelihood of individual pipes

2011 ◽  
Vol 14 (3) ◽  
pp. 659-681 ◽  
Author(s):  
Yehuda Kleiner ◽  
Balvant Rajani
Keyword(s):  
Water Distribution ◽  
Distribution Networks ◽  
Classification Model ◽  
Pipe Material ◽  
Homogeneous Poisson Process ◽  
Model Based ◽  
Water Mains ◽  
Natural Variations ◽  
Non Homogeneous Poisson Process ◽  
Subsequent Failure

The use of statistical methods to discern patterns of historical breakage rates and use them to predict water main breaks has been widely documented. Particularly challenging is the prediction of breaks in individual pipes, due to the natural variations that exist in all the factors that affect their deterioration and subsequent failure. This paper describes alternative models developed into operational tools that can assist network owners and planners to identify individual mains for renewal in their water distribution networks. Four models were developed and compared: a heuristic model, a naïve Bayesian classification model, a model based on logistic regression and finally a probabilistic model based on the non-homogeneous Poisson process (NHPP). These models rank individual water mains in terms of their anticipated breakage frequency, while considering both static (e.g. pipe material, diameter, vintage, surrounding soil, etc.) and dynamic (e.g. climate, operations, cathodic protection, etc.) effects influencing pipe deterioration rates.

scholarly journals Some explicit formulations of Colebrook–White friction factor considering accuracy vs. computational speed

2010 ◽  
Vol 13 (3) ◽  
pp. 401-418 ◽  
Author(s):  
O. Giustolisi ◽  
L. Berardi ◽  
T. M. Walski
Keyword(s):  
Friction Factor ◽  
Water Distribution ◽  
Polynomial Regression ◽  
Optimization Problems ◽  
Distribution Networks ◽  
Computational Burden ◽  
Evolutionary Polynomial Regression ◽  
Large Size ◽  
Computational Speed ◽  
The One

The Colebrook–White formulation of the friction factor is implicit and requires some iterations to be solved given a correct initial search value and a target accuracy. Some new explicit formulations to efficiently calculate the Colebrook–White friction factor are presented herein. The aim of this investigation is twofold: (i) to preserve the accuracy of estimates while (ii) reducing the computational burden (i.e. speed). On the one hand, the computational effectiveness is important when the intensive calculation of the friction factor (e.g. large-size water distribution networks (WDN) in optimization problems, flooding software, etc.) is required together with its derivative. On the other hand, the accuracy of the developing formula should be realistically chosen considering the remaining uncertainties surrounding the model where the friction factor is used. In the following, three strategies for friction factor mapping are proposed which were achieved by using the Evolutionary Polynomial Regression (EPR). The result is the encapsulation of some pieces of the friction factor implicit formulae within pseudo-polynomial structures.

An iterative method for leakage zone identification in water distribution networks based on machine learning

2020 ◽  
pp. 147592172095047
Author(s):  
Jingyu Chen ◽  
Xin Feng ◽  
Shiyun Xiao
Keyword(s):  
Random Forest ◽  
Iterative Method ◽  
Water Distribution ◽  
Pressure Sensors ◽  
Distribution Networks ◽  
Random Forest Classifier ◽  
Identification Accuracy ◽  
Water Distribution Networks ◽  
Minimum Number ◽  
Leakage Characteristics

For leakage identification in water distribution networks, if each node is used as a category label of the classifier model, the accuracy of the classifier model will be low because of similar leakage characteristics. By clustering the nodes with similar leakage characteristics and using all the possible combinations of leakages as the category labels of the classifier model, the accuracy of the classifier model for leakage location can be improved. An iterative method combining k-means clustering with the random forest classifier is proposed to identify the leakage zones. In each iteration, k-means clustering is used to divide the leakage zone identified in the previous iterations into two zones, and then, the random forest classifier is used to identify the leakage zones and the number of leakages in each leakage zone. As the number of iterations increases, the number of candidate leakage zones and sensors that conduct leakage zone identification decreases. Thus, feature selection can be used in each iteration to select the minimum number of sensors for model training without affecting identification accuracy. Three leakage scenarios are considered: a single leakage, two simultaneous leakages, and four simultaneous leakages. A benchmark case is presented in this study to demonstrate the effectiveness of the proposed method. The influences of the number of pressure sensors and Gaussian noise level on the identification results are also discussed. Results indicate that the proposed method is effective for identifying simultaneous leakages.

Disturbance Extraction for Burst Detection in Water Distribution Networks Using Pressure Measurements

2020 ◽  
Vol 56 (5) ◽  
Author(s):  
Weirong Xu ◽  
Xiao Zhou ◽  
Kunlun Xin ◽  
Joby Boxall ◽  
Hexiang Yan ◽  
...  
Keyword(s):  
Water Distribution ◽  
Distribution Networks ◽  
Water Distribution Networks ◽  
Pressure Measurements ◽  
Burst Detection

Pressure variation and effective sensing zone around small leaks inside water pipelines for reliable leak detection

2015 ◽  
Vol 231 (3) ◽  
pp. 590-599
Author(s):  
Atia E Khalifa
Keyword(s):  
Pressure Drop ◽  
Water Distribution ◽  
Leak Detection ◽  
Distribution Networks ◽  
Pressure Variation ◽  
Pressure Probe ◽  
Pressure Measurements ◽  
Local Pressure ◽  
Measured Pressure ◽  
Pipeline Pressure

Detecting and locating small leaks in the water distribution networks save water and help in making critical decisions about the network and the infrastructure. In this work, inside-pipe pressure measurements are used to evaluate the local variation of the pressure around small circular leaks as compared to main pipeline pressure, for reliable leak detection. The technique is working for pressurized pipelines and may be used for liquids and gases. In addition, since large leaks are easy to find, the attention is given to detecting small leaks, which are difficult to be detected using the commercial acoustic methods; specifically with plastic pipes. The current study thereafter helps in characterizing the effective zone of pressure sensing around the leak. A pressure probe, mounted on a movable platform, moves inside a water-pressurized pipe very close to the wall in order to measure the pressure variation at the vicinity of the leak. The effects of pipeline pressure, leak size, and the clearance distance between the pipe wall and the pressure probe on the measured pressure drop around the leak are investigated. Results showed that direct pressure measurements inside the pipe can be effectively used for leak detection. The local pressure drop due to the small leak is very localized around the leak and captured within the leak diameter in the longitudinal direction and almost leak-like radius above the leak in the radial direction. As the line pressure increases, the measured pressure drop increases but the zone of pressure variation is still confined around the leak itself. If the sensor is moving over the leak, then the magnitude of the measured pressure drop is inversely proportional to the sensor speed inside the pipe.

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