The present volume contains the Proceedings of the 14th International Conference on Hydroinformatics – HIC 2022, held from the 4th to the 8th of July 2022 in Bucharest, Romania. The conference was ...jointly organised by the Technical University of Civil Engineering Bucharest and the University “Politehnica” of Bucharest.
Abstract
The paper focuses on the numerical modelling of a rural Water Distribution System (WDS), supplied from a deep well, from which the water is pumped in a water tower (storage tank). Consumers ...are fed gravitationally from the water tower, with variable demand over 24 hours. Simulations were carried out in EPANET 2.2 using two methods: Demand Driven Analysis (DDA) with outflow issuing from emitters, and Pressure Driven Analysis (PDA). To minimize numerical instabilities, a particular attention was paid to the groundwater well (modelled both with variable, and constant hydrodynamic level), as well as to the connection of the water tower to WDS (where the connection was made either using 2 pipes, or a single pipe). By applying the DDA and PDA methods to the resulting 2×2 configurations of the hydraulic system, a total of 8 sets of simulations (solutions) were obtained and compared. The most advantageous pair of method and configuration is recommended to be considered when modelling a complex (e.g. urban size) WDS with groundwater supply and storage tanks.
EPANET modeling of an urban groundwater field Iancu, Iulian; Dimache, Alexandru-Nicolae; Georgescu, Sanda-Carmen ...
E3S Web of Conferences,
01/2019, Letnik:
85
Journal Article, Conference Proceeding
Recenzirano
Odprti dostop
The paper presents an EPANET model of a groundwater well field. The method used in the simulations to model the variation of the hydrodynamic levels in wells as a function of the pumped flow rate is ...discussed, and a comparison to previous simulations that used fixed hydrodynamic levels in the wells is performed. The case study points to a groundwater well field in Romania. The results show that the new method although requiring a more complex EPANET model, provides a solution that is closer to the actual variation of water levels in wells.
Abstract
The present study focuses on the operation of a drip irrigation system for greenhouses rose cultivation in Adunatii-Copaceni, Giurgiu County, Romania. The numerical modelling of the ...irrigation system was performed in EPANET 2.2, using the pressure driven demand model. The pumping schedule fits the real operation, where five greenhouses are irrigated successively each morning, directly through pumping from a groundwater source. Fertigation is applied for each greenhouse every 5 days, in the evening, through pumping from a storage tank. Despite the hydraulic assumptions adopted to model the groundwater well and dripper lines, the computed results match the values of the outflow rates measured for the dripper lines of the real drip irrigation system. Simulations are useful to investigate, at no cost, different scenarios attached to the operation of the studied drip irrigation system.
This paper focuses on a methodology allowing to derive the pumping schedule in Water Distribution Networks (WDN), upon a time dependent water demand. The selected test case is a previously studied ...WDN. Two pumping algorithms give different pumping rules. By solving the nonlinear system of equations, consisting of energy balance equations, mass balance equations and pumping rules, one gets the pumps speed factors. Solutions attached to the Pressure Driven Analysis (PDA) correspond to energy and cost savings, with respect to the solutions given by the Demand Driven Analysis (DDA). The methodology described in this paper is simple and rapid, but the iterative numerical method used to solve the system of equations is highly dependent on the starting guess.
This paper focuses on the Cooling Water System (CWS) of Vidraru Hydro-Power Plant (HPP) − a 220 MW underground HPP, on the Arges River in Romania. It is equipped with 4 high head vertical Francis ...turbines of 55 MW each, 4 hydropower generators of 61 MVA each, and 7 step-up transformers of 40 MVA each. The goal is to model the above CWS and to analyse the system response under normal and critical operating scenarios. The numerical model built in EPANET is complex: the cooling water network is normally fed by pumping from the underground tailrace (using up to 3 pumps of 110kW each), but there is a backup supplying circuit fed directly from the penstock bifurcation pipe (using pressure reducing valves). Within the power plant, the following equipments need cooling water: air-water heat exchangers (related to generators and HVAC system); oil-water heat exchangers (related to bearings, speed governors and transformers); coolers of the turbines seals. Since EPANET lacks such physical components, they are artificially replaced by throttle control valves set with equivalent loss coefficients, established upon pressure drop values available for each equipment. The computed flow rate and pressure values match the existing recordings for normal operation. The numerical model also provides data on the system behaviour under critical operation conditions, e.g. when the HPP is operating at full capacity with CWS fed only by 2 pumps, out of 3 available pumps.
The present case study points on the cooling water system of the Hydro-Power Plant (HPP) Bradisor, on the Lotru River in Romania. This 115 MW underground power plant is equipped with two Francis ...turbines. We built in EPANET a numerical model to simulate the operation of the cooling water system of this HPP, for different working scenarios. The whole hydraulic system is a complex one: it is composed of a main cooling water network fed by pumps, a water-based fire fighting network for the hydropower generators and a backup cooling water network fed from the penstock pipes. The numerical model of the whole cooling water system consists of 87 pipes, 133 junctions, 6 variable speed driven centrifugal pumps, 59 valves and 3 reservoirs. Some throttle control valves (TCV) are artificially inserted in our numerical model and are set with appropriate loss coefficients values to be equivalent to the equipments that introduce minor losses in the system and don’t exist as physical components in EPANET. Those equipments are: air-water heat exchangers (placed around the hydropower generators), oil-water heat exchangers (of heavy-duty thrust bearings, of turbines’ and generators’ guide bearings, of the 130 MVA step-up transformer), coolers of turbines’ seals and self-cleaning filters (one for each hydropower unit and another one for the transformer). The loss coefficient for each equivalent TCV was set based on pressure loss values measured in situ on each equipment. The numerical results (pressure and flow rate values) match the existing recordings. The simulations prove that by using a proper calibration of the numerical model, EPANET capabilities can be extended for more complex systems than the water distribution systems.
The paper focuses on the dry fountains (pedestrian type fountains) recently commissioned in the campus of the University POLITEHNICA of Bucharest (UPB), consisting of 12 water jets in a straight ...line. Each water jet rises from an A-type nozzle installed just below the pedestrian level, upon a water flow pattern that is individually controlled by an adjustable fountain pump. LED spotlights are installed into the pavement for each nozzle. An intelligent control system drives the fountains, to produce a water show, based on dancing jets and different light colours. The operation of Dry Fountains of UPB was modelled using GNU Octave and AutoCAD software, to mimic the dancing jets. The proposed theoretical approach allows computing the electric energy consumption of the fountains, for a water show full sequence derived from video recordings, based on hydraulic and mechanical parameters attached to the numerical model that mimics the real hydraulic system.
The operation of pumps within a pumping station can be controlled by the Pressure Set Point (PSP) value compared to the reading of a pressure sensor placed either at the exit of the pumping station, ...on the main discharge pipe (classical PSP method), or at a critical/monitoring point within the water distribution network (termed further as remote-control PSP method). We designed and built an experimental test rig, allowing to study both control methods, in the attempt to check the advantage of the remote-control PSP method, with respect to the classical PSP method, since governing equations show that they are equivalent. The design relies on the theoretical approach and numerical results presented within this paper.
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