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Modelling of water network systems. Prof Tiit Koppel Department of Mechanics Tallinn University of Technology October 13, 2008. Contents. Department of Mechanics Modelling Reconstruction Leakages Hydraulic Efficiency Calibration.
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Modelling of water network systems Prof Tiit Koppel Department of Mechanics Tallinn University of Technology October 13, 2008
Contents Department of Mechanics Modelling Reconstruction Leakages Hydraulic Efficiency Calibration
DepartmentofMechanicsTheFacultyofCivilEngineering Chair of Technical Mechanics Laboratory of Strength of Materials Chair of Hydromechanics Laboratory of Hydromechanics Chair of Applied Mechanics
Research and Applied Projects Target Financing of Estonia SF0140072s08 “Mechanics of fluid-structure interaction”, 2008-2013 ESF Grant 6169 “Non-destructive control of pipes using Lamb waves”, 2005-2008 ESF Grant 6740 “The effect of the shear stiffness on the bending of a passenger ship”, 2006-2009 ESF Grant 7646 “Dynamics of liquid flow in pressure pipes”, 2008-2011
Research and Applied Projects 6th Framework HYDRALAB III Integrated Infrastructure Project “Unsteady friction in pipes and ducts”, Deltares, Delft, 2007-2008 6th Framework HYDRALAB III Integrated Infrastructure Project “Transient vaporous and gaseous cavitation in pipelines”, Deltares, Delft, 2008-2009 SWECO Project AS “Investigation of storm water in Tallinn”, 2008
Research and Applied Projects OÜ Qcell “Flue gas and CO2 for the growing of algae”, 2008-2010 INNOVE Project “Invitation of foreign lecturers to open in the Faculty of Civil Engineering a new specialization – Port Construction and Coastal Engineering”, 2005-2008
Subjects of Modelling Model skeletonization Demand allocation using GIS Water quality sampling and calibration Integrating modelling and SCADA systems Genetic-algorithm-based calibration and design Modelling variable-speed pumps Water system security Hydraulic transients Using flow emmiters Integrating GIS with hydraulic modelling
Application of Models • Long-range master planning • Fire protection studies • Water quality investigations • Energy management • System design • Risk analysis • Daily operations
Model Based Leak Detection 1/2 • Deterministic approaches: - most of present methods - single value for leak location and size • Probabilistic approaches: - very little research undertaken - a value with the associated probability for leak location and size is given
Model Based Leak Detection 2/2 Deterministic vs. Probabilistic Leak size: 20 units/second (with probability of 0.1) Leak size: 20 units/second Leak size: 2 units/second Leak size: 2 units/second (with probability of 0.8) AREA 1 AREA 2
SCEM-UA Based ProbabilisticLeak Detection Methodology • Shuffled Complex Evolution Metropolis algorithm • For leak detection purposes, EPANET software linked to the SCEM-UA algorithm in the MATLAB environment • Methodology has been tested with real network data (Rakvere City network)
Examples of the Results • PDF captures the probabilistic beliefs about the parameters in the light of the observed data TRUE = 0.5 SCEM-UA: AV = 0.28 TRUE = 3.00 SCEM-UA: AV = 1.81
The Advantages of the Methodology • Both the leak size and the associated error (i.e. uncertainty) can be determined in a single, optimisation type model run. • The probability density function can be continuously updated when additional information about the system becomes available.
Further Studies Continues • The possibility to use other pressure dependent leakage model equation that includes more info about network itself (seek a broken pipe not just node!) • Alternative WDS models (e.g. extended period simulation) might come into effect when analysing real life systems. • Use of additional type of measurements (e.g. flows). Measuring pressures at low flows does not give valuable information about the network
Diurnal Water Consumption 68 elamut (7 päeva)
Diurnal Leakage Dynamic sL = 1 , kH0 = 10, q0 = 10, β0 = 1, β1 = -0.5, β2 = -0.4
Methodology of ModelCalibrationin TUT • use much faster algorithm than GA. • use preliminary analysis to find unaccounted consumption and real losses for the whole WDS. • includes possibilities to use pressure differentials instead of pressures for calibration. It eliminates influence of wrong elevation of nodes and reduce influence of leakages on calibration results.
Analysis of the Patterns in Order to Find Unaccounted Consumption and Real Losses where - Pattern of i-th demand - Pattern of leakages After this first iteration of calibration and analysis of errors
Analysis of the Dynamics of Errors Dependence of errors on water flow because of a) wrong demand and roughness; b) leakages
Comparison of the Results Obtained by Calibration Using Pressures and Pressure Differentials