scholarly journals Limitations of demand- and pressure-driven modeling for large deficient networks

2017 ◽  
Vol 10 (2) ◽  
pp. 93-98 ◽  
Author(s):  
Mathias Braun ◽  
Olivier Piller ◽  
Jochen Deuerlein ◽  
Iraj Mortazavi
Keyword(s):  
Water Distribution ◽  
Network Models ◽  
Distribution Networks ◽  
Computer Applications ◽  
State Variables ◽  
Modeling Process ◽  
Uniqueness Of The Solution ◽  
Basic Equations ◽  
Physical Phenomena ◽  
Pressure Driven

Abstract. The calculation of hydraulic state variables for a network is an important task in managing the distribution of potable water. Over the years the mathematical modeling process has been improved by numerous researchers for utilization in new computer applications and the more realistic modeling of water distribution networks. But, in spite of these continuous advances, there are still a number of physical phenomena that may not be tackled correctly by current models. This paper will take a closer look at the two modeling paradigms given by demand- and pressure-driven modeling. The basic equations are introduced and parallels are drawn with the optimization formulations from electrical engineering. These formulations guarantee the existence and uniqueness of the solution. One of the central questions of the French and German research project ResiWater is the investigation of the network resilience in the case of extreme events or disasters. Under such extraordinary conditions where models are pushed beyond their limits, we talk about deficient network models. Examples of deficient networks are given by highly regulated flow, leakage or pipe bursts and cases where pressure falls below the vapor pressure of water. These examples will be presented and analyzed on the solvability and physical correctness of the solution with respect to demand- and pressure-driven models.

scholarly journals Limitations of Demand- and Pressure-Driven Modeling for Large Deficient Networks

2017 ◽  
Author(s):  
Mathias Braun ◽  
Olivier Piller ◽  
Jochen Deuerlein ◽  
Iraj Mortazavi
Keyword(s):  
Water Distribution ◽  
Network Models ◽  
Distribution Networks ◽  
Computer Applications ◽  
State Variables ◽  
Modeling Process ◽  
Uniqueness Of The Solution ◽  
Basic Equations ◽  
Physical Phenomena ◽  
Pressure Driven

Abstract. The calculation of hydraulic state variables for a network is an important task in managing the distribution of potable water. Over the years the mathematical modeling process has been improved by numerous researchers for the utilization in new computer applications and the more realistic modeling of water distribution networks. But, in spite of these continuous advances, there are still a number of physical phenomena that cannot be tackled correctly by current models. This paper will take a closer look on the two modeling paradigms given by demand and pressure driven modeling. The basic equations are introduced and parallels are drawn to the optimization formulations from electrical engineering. These formulations guarantee existence and uniqueness of the solution. One of the central questions in the French and German research project ResiWater is the investigation of the network resilience in case of extreme events or disasters. Under such extraordinary conditions where models are pushed beyond their limits we talk of deficient network models. Examples of deficient networks are given by highly regulated flow, leakage or pipe bursts and cases where pressure falls below the vapor-pressure of water. These examples will be presented and analyzed on the solvability and physical correctness of the solution with respect to demand and pressure driven models.

scholarly journals Optimal Placement of Pressure Gauges for Water Distribution Networks Using Entropy Theory Based on Pressure Dependent Hydraulic Simulation

Entropy ◽  
2018 ◽  
Vol 20 (8) ◽  
pp. 576 ◽  
Author(s):  
Do Yoo ◽  
Dong Chang ◽  
Yang Song ◽  
Jung Lee
Keyword(s):  
Water Distribution ◽  
Pressure Gauge ◽  
Distribution Networks ◽  
Entropy Method ◽  
Water Distribution Networks ◽  
Optimal Placement ◽  
Hydraulic Simulation ◽  
Priority Order ◽  
The Impact ◽  
Pressure Driven

This study proposed a pressure driven entropy method (PDEM) that determines a priority order of pressure gauge locations, which enables the impact of abnormal condition (e.g., pipe failures) to be quantitatively identified in water distribution networks (WDNs). The method developed utilizes the entropy method from information theory and pressure driven analysis (PDA), which is the latest hydraulic analysis method. The conventional hydraulic approach has problems in determining the locations of pressure gauges, attributable to unrealistic results under abnormal conditions (e.g., negative pressure). The proposed method was applied to two benchmark pipe networks and one real pipe network. The priority order for optimal locations was produced, and the result was compared to existing approach. The results of the conventional method show that the pressure reduction difference of each node became so excessive, which resulted in a distorted distribution. However, with the method developed, which considers the connectivity of a system and the influence among nodes based on PDA and entropy method results, pressure gauges can be more realistically and reasonably located.

scholarly journals Leakage Calibration in Water Distribution Networks with Pressure-Driven Analysis: A Real Case Study

2020 ◽  
Vol 2 (1) ◽  
pp. 59
Author(s):  
Joaquim Sousa ◽  
Nuno Martinho ◽  
João Muranho ◽  
Alfeu Sá Marques
Keyword(s):  
Water Distribution ◽  
Simulated Annealing Algorithm ◽  
Distribution Networks ◽  
Water Distribution Networks ◽  
Real Case ◽  
Calibration Process ◽  
Pressure Step ◽  
Water Companies ◽  
Pressure Driven

Leakage in water distribution networks (WDN) is still a major concern for water companies. In recent years, the scientific community has dedicated some effort to the leakage calibration issue to obtain accurate models. But leakage modelling implies the use of a pressure-driven approach as well as specific data to define the pressure/leakage relationship. This paper presents the calibration process of a real case study WDN model. The process started with pressure step tests, the model was built in WaterNetGen and the leakage calibration process was performed by a simulated annealing algorithm. As illustrated, after calibration the model was able to produce accurate results.

scholarly journals A New Set of Local Indices Applied to a Water Network through Demand and Pressure Driven Analysis (DDA and PDA)

Water ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 2210 ◽  
Author(s):  
Marco Amos Bonora ◽  
Fabio Caldarola ◽  
Mario Maiolo
Keyword(s):  
Water Distribution ◽  
Distribution Networks ◽  
Operating Regime ◽  
Hydraulic Modeling ◽  
Mathematical Framework ◽  
Water Network ◽  
Model Assumption ◽  
Drinking Water Distribution ◽  
Pressure Driven Analysis ◽  
Pressure Driven

In the analysis of drinking Water Distribution Networks (WDNs), performance indices are widely used tools for obtaining synthetic information about the WDN operating regime (pressures and flows). This paper presents applications of a series of local surplus indices that act in a new mathematical framework. This framework allows reworking many well-known performance and energetic indices and simultaneously allowing analysis of specific aspects of the WDN. The analyses are carried out using different resolutive hydraulic approaches: the Demand-Driven Analysis (DDA) and the Pressure-Driven Analysis (PDA), typical of software such as EPANET and WaterNetGen. The authors analyse the hypotheses necessary for the application of these models, and how these influence the results of both the hydraulic modeling and the resilience indices assessment. In particular, two resilience indices are reformulated through the new local surplus indices and all of them are then simulated in different conditions for a water network known in literature as the Kang and Lansey WDN. The solving model assumption effects are deepen, reporting graphical and numerical results for different consumption scenarios and the different hydraulic approaches used.

scholarly journals An Interface Extension for the New EPANET 2.X

2020 ◽  
Vol 2 (1) ◽  
pp. 60
Author(s):  
João Muranho ◽  
Ana Ferreira ◽  
Joaquim Sousa ◽  
Abel Gomes ◽  
Alfeu Sá Marques
Keyword(s):  
Graphical User Interface ◽  
Water Distribution ◽  
Distribution Networks ◽  
Release Dates ◽  
Dynamic Link Library ◽  
Backward Compatibility ◽  
Implementation Aspects ◽  
Public Domain Software ◽  
Model Water ◽  
Pressure Driven

The EPANET 2.0 is a public domain software used to model water distribution networks. The last main release dates to 2000. Recently, the Open Source EPANET Initiative has fixed some bugs and has brought new features to the EPANET solver, such as improved convergence or pressure-driven simulation, and has released it under a new version: EPANET 2.2. Although the legacy Graphical User Interface (GUI) still works with the updated Dynamic Link Library (DLL) (backward compatibility), it does not access the new features. This paper proposes and explores a GUI extension that takes advantage of the new pressure-driven features (such as pressure deficit or demand deficit). The paper also discusses some implementation aspects of the new solver that should be revisited in future releases.

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