Pipe roughness calibration approach for water distribution network models (original) (raw)

Liénard type model of fluid flow in pipelines: Application to estimation

This paper highlights how fluid flow in a pipeline can be represented as a nonlinear model of so-called Liénard type. It is then shown how the structure of this model is suitable for the design of algorithms to identify parameters of a pipeline or estimate unmeasurable states. This approach is illustrated by simulation results, for instance showing how to estimate the Darcy-Weisbach friction coefficient or the fluid acceleration.

Friction estimation of pipelines with extractions by using state observers

This article proposes an approach based on state observers to recursively estimate the friction of pipelines with an extraction. Two specific scenarios, associated with information availability, are treated herein: (1) pressure at the extraction is measurable, (2) extraction measurements are unavailable but the position is known. For both scenarios, measurement availability at the pipeline ends is assumed. The state observers were designed from Liénard type models that represent the fluid dynamics in a pipeline. Such models were extended with the incorporation of the friction factors into their state vectors, such that from the extended models, the observers were constructed. The proposed approach was tested by using data from the commercial software PipelineStudio and experimental data from a laboratory pipeline of water.

Examples of pipeline monitoring with nonlinear observers and real-data validation

2011

This article shows how nonlinear observers can be used as tools for the monitoring of pipelines. In particular two observer approaches for two different applications are presented: a one-leak detection and isolation problem on the one the hand, and the same problem with friction estimation in addition on the other hand. In the first case, the system which represents the pipeline with a leak satisfies some uniform observability condition allowing for the design of a classical high gain observer (with a static Lyapunov equation). In the second case, the system is no longer uniformly observable, but still satisfies the observability rank condition, and an Extended Kalman Filter is proposed, under the use of exciting inputs. In both cases, experimental results are provided.

Calibration of a model of an operational water distribution system containing pipes of different age

Advances in Engineering Software, 2009

The aim of the paper is to demonstrate that the Levenberg-Marquardt algorithm can give successful results when operational water distribution systems are calibrated with the proper selection of parameter increment for the calculation of partial derivatives. The functional dependence of pipe roughness on age, which describes linear and nonlinear dependences, is proposed for the calibration of a model of a water distribution system containing pipes of different age. It is also shown that the visualization of response surface on a coarse grid is very useful for the analysis of the results.

Considerations On The Validation Of PipeNetwork Using Unsteady Flow Equations

1970

A technique to verify the looped water supply networks, using unsteady flow equations, has been applied utilizing several pipe networks. The analysis of the results of these tests has allowed the authors to develop some considerations on value to attribuite to two hydrodynamic parameters (celerity and friction factor). These issues are been useful to simplify the computer code and to reduct the calculation times.

Flexible Framework for Modeling Water Conveyance Networks

A flexible framework for modeling different water conveyance networks is presented. The network is modeled using a linear canal pool model based on the Saint-Venant equations to describe transportation phenomenon occurring in open channels. This model is used as a link to connect different nodes defined by gates or reservoirs. The linear pool model has interesting features namely the pool axis monitoring, the inflow along the pool axis and the ability to consider different boundary conditions. Based on these characteristics canal pool observers for leak detection and localization can be developed. It is shown that based on a finite difference scheme a good performance is obtained for low space resolution. The modeling framework is validated with experimental data from a real canal property of theÉvora University. This is a challenging configuration due to its strong canal pool coupling.

Joint Physical and Numerical Modeling of Water Distribution Networks

2009

This report summarizes the experimental and modeling effort undertaken to understand solute mixing in a water distribution network conducted during the last year of a 3-year project. The experimental effort involves measurement of extent of mixing within different configurations of pipe networks, measurement of dynamic mixing in a single mixing tank, and measurement of dynamic solute mixing in a combined network-tank configuration. High resolution analysis of turbulence mixing is carried out via high speed photography as well as 3D finite-volume based Large Eddy Simulation turbulence models. Macroscopic mixing rules based on flow momentum balance are also explored, and in some cases, implemented in EPANET. A new version EPANET code was developed to yield better mixing predictions. The impact of a storage tank on pipe mixing in a combined pipe-tank network during diurnal fill-and-drain cycles is assessed. Preliminary comparison between dynamic pilot data and EPANET-BAM is also reported.

Developed hydraulic simulation model for water pipeline networks

Alexandria Engineering Journal, 2013

A numerical method that uses linear graph theory is presented for both steady state, and extended period simulation in a pipe network including its hydraulic components (pumps, valves, junctions, etc.). The developed model is based on the Extended Linear Graph Theory (ELGT) technique. This technique is modified to include new network components such as flow control valves and tanks. The technique also expanded for extended period simulation (EPS). A newly modified method for the calculation of updated flows improving the convergence rate is being introduced. Both benchmarks, ad Actual networks are analyzed to check the reliability of the proposed method. The results reveal the finer performance of the proposed method.

About friction modeling for observer-based leak estimation in pipelines

IEEE Conference on Decision and Control and European Control Conference, 2011

A study of the friction model for the leak detection with a nonlinear observer is presented. Classically the friction model in leak detection algorithms only relies on a constant parameter. In the present work, the use of a more elaborate friction model is considered, with a coefficient explicitly depending on the flow, either algebraically, or even differentially. Those friction formulations are implemented within a nonlinear-observer-based algorithm for detection and location of leaks, which is analyzed, and tested with real measurements on some experimental pipeline prototype. Some conclusions and recommendations about this extended friction modeling are finally given.

Estimation of Hydraulic Gradient for a Transport Pipeline

Journal of Pressure Vessel Technology, 2020

This work deals with the hydraulic gradient estimation in real-time of a transport pipeline computational model by considering a slightly compressible fluid and slightly deformable conduit walls. Since the hydraulic gradient (J(Q)) caused by the friction phenomenon in a pipeline plays an important role in the system's behavior, and this function is affected by fluid properties' deviations, environmental disturbances and conduit deteriorations, it is proposed that the on-line estimation of J(Q) could be part of a monitoring system. The proposition can be applied to obtain computational models of a line with a junction and assumes only measurements of pressure and flow rate at the ends of the conduit and the junction outflow. The generic form of the gradient function J(Q) is a second-order polynomial with coefficients that involve indirectly pipe roughness, the transversal area of the conduit, fluid viscosity and elements connected to the line. The extended Kalman filter (EKF) is applied to estimate the coefficients of the function J(Q). As a test apparatus, a 163 m long hydraulic pipeline is used. Diverse experiments show the usefulness of the on-line estimation of J(Q) for monitoring and simulation tasks where computational models are necessary.