Browsing by Author "Fuertes Miquel, Vicente S."

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2D CFD Modeling of Rapid Water Filling with Air Valves Using OpenFOAM
(2021-11-04) Aguirre-Mendoza, Andres M.; Oyuela, Sebastián; Espinoza Román, Héctor Gabriel; Coronado-Hernández, Oscar E.; Fuertes Miquel, Vicente S.; Paternina-Verona, Duban A.
The rapid filling process in pressurized pipelines has been extensively studied using mathematical models. On the other hand, the application of computational fluid dynamics models has emerged during the last decade, which considers the development of CFD models that simulate the filling of pipes with entrapped air, and without air expulsion. Currently, studies of CFD models representing rapid filling in pipes with entrapped air and with air expulsion are scarce in the literature. In this paper, a two-dimensional model is developed using OpenFOAM software to evaluate the hydraulic performance of the rapid filling process in a hydraulic installation with an air valve, considering different air pocket sizes and pressure impulsion by means of a hydro-pneumatic tank. The two-dimensional CFD model captures the pressure evolution in the air pocket very well with respect to experimental and mathematical model results, and produces improved results with respect to existing mathematical model
A parametric sensitivity analysis of numerically modelled piston-type filling and emptying of an inclined pipeline with an air valve
(BHR Group Limited, 2018) Coronado Hernández, Óscar Enrique; Fuertes Miquel, Vicente S.; Besharat M.; Ramos H.M.
Filling and emptying operations should be planned by engineers in operational stages to prevent a system failure depending on reaching extreme low pressure values. In this sense, a compression of an air pocket produces pressure surges, while an expansion generates troughs of subatmospheric pressure. A sensitivity analysis of main hydraulic and thermodynamic parameters was conducted based on a mathematical model developed by the authors. A case study was selected to see the influence of different parameters. When the filling operation is performed, the more sensible parameters are pipe slope, air valve size, internal pipe diameter, and friction factor; while, the emptying operation shows that air valve size, air pocket size, pipe slope, and internal pipe diameter are the more sensible parameters. © 2018 BHR Group.
Analysis of hydraulic transients during pipeline filling processes with air valves in large-scale installations
(2020-04-13) Fuertes Miquel, Vicente S.; Coronado Hernández, Óscar Enrique; Ponz-Carcelén Roman; Romero, Guillermo; Ponz-Carcelén, Román; Biel-Sanchis, Francisco
During the filling process in pressurized hydraulic systems, sudden pressure changes generated inside the pipes can cause significant damage. To avoid these excessive overpressures, air valves should be installed to allow air exchange between the inside and outside during the filling process. This study presents a mathematical model to analyse the hydraulic transients during filling processes. This model, which has already been validated in small laboratories, is now applied to real large-scale systems that consist of DN400 and DN600 pipelines from Empresa Mixta Metropolitana S.A (EMIMET – Group Global Omnium), which is the company that manages the water supply of the metropolitan area of Valencia (from the Drinking Water Treatment Station to the municipalities). The mathematical model for large pipes is validated by comparing the experimental measurements and the results of model.
Analysis of sub-atmospheric pressures during emptying of an Irregular pipeline without an air valve using a 2D CFD model
(2021-09-15) Hurtado-Misal, Aris D.; Hernández-Sanjuan, Daniela; Coronado Hernández, Óscar Enrique; Espinoza Román, Héctor Gabriel; Fuertes Miquel, Vicente S.
Studying sub-atmospheric pressure patterns in emptying pipeline systems is crucial because these processes could cause collapses depending on the installation conditions (the underground pipe covering height, type, fill, and pipeline stiffness class). Pipeline studies have focused more on filling than on emptying processes. This study presents an analysis of the following variables: air pocket pressure, water velocity, and water column length during the emptying of an irregular pipeline without an air valve by two-dimensional computational fluid dynamics (2D CFD) model simulation using the software OpenFOAM. The mathematical model predicts the experimental values of the study variables. Water velocity vectors are also analysed within the experimental facility, assessing the sensitivity of the drain valve to different openings and changes in water column length during the hydraulic phenomenon.
Assessment of Steady and Unsteady Friction Models in the Draining Processes of Hydraulic Installations
(2021-07-08) Coronado Hernández, Óscar Enrique; Derpich, Ivan; Fuertes Miquel, Vicente S.; Coronado Hernández, Jairo Rafael; Gatica, Gustavo
The study of draining processes without admitting air has been conducted using only steady friction formulations in the implementation of governing equations. However, this hydraulic event involves transitions from laminar to turbulent flow, and vice versa, because of the changes in water velocity. In this sense, this research improves the current mathematical model considering unsteady friction models. An experimental facility composed by a 4.36 m long methacrylate pipe was configured, and measurements of air pocket pressure oscillations were recorded. The mathematical model was performed using steady and unsteady friction models. Comparisons between measured and computed air pocket pressure patterns indicated that unsteady friction models slightly improve the results compared to steady friction models.
Backflow air and pressure analysis in emptying a pipeline containing an entrapped air pocket
(Taylor and Francis Ltd., 2018) Besharat M.; Coronado Hernández, Óscar Enrique; Fuertes Miquel, Vicente S.; Viseu M.T.; Ramos H.M.
The prediction of the pressure inside the air pocket in water pipelines has been the topic for a lot of research works. Several aspects in this field have been discussed, such as the filling and the emptying procedures. The emptying process can affect the safety and the efficiency of water systems. Current research presents an analysis of the emptying process using experimental and computational results. The phenomenon is simulated using the two-dimensional computational fluid dynamics (2D CFD) and the one-dimensional mathematical (1D) models. A backflow air analysis is also provided based on CFD simulations. The developed models show good ability in the prediction of the sub-atmospheric pressure and the flow velocity in the system. In most of the cases, the 1D and 2D CFD models show similar performance in the prediction of the pressure and the velocity results. The backflow air development can be accurately explained using the CFD model. © 2018, © 2018 Informa UK Limited, trading as Taylor & Francis Group.
CFD and 1D simulation of transient flow effect on air vessel
(BHR Group Limited, 2018) Besharat M.; Coronado Hernández, Óscar Enrique; Fuertes Miquel, Vicente S.; Viseu M.T.; Ramos H.M.
The estimation of unsteady parameters in two-phase condition is crucial for the safety and reliability of the hydraulic systems. There are plenty of one-dimensional (1D) simulation tools for unsteady flow estimation being some of them able to present good results in monophasic flows, while almost all of them are not suitable for two-phase flows. In this research, an experimental apparatus including valves, pipes and an air vessel is used to fulfil the experiments. A mathematical formulation and a two-dimensional computational fluid dynamics (2D CFD) model have been used to predict the extreme conditions. Results show that 1D model is able to predict pressure values with acceptable accuracy. However, the 2D CFD model can be used to detect the specialized problems in a system by providing very high range of the information. © BHR Group 2018 Pressure Surges 13
Closure to "rigid Water Column Model for Simulating the Emptying Process in a Pipeline Using Pressurized Air" by Oscar E. Coronado-Hernández, Vicente S. Fuertes-Miquel, Pedro L. Iglesias-Rey, and Francisco J. Martínez-Solano
(American Society of Civil Engineers (ASCE), 2020) Coronado Hernández, Óscar Enrique; Fuertes Miquel, Vicente S.; Iglesias-Rey P.L.; Martínez-Solano F.J.
Computational fluid dynamics for sub-atmospheric pressure analysis in pipe drainage
(Taylor and Francis Ltd., 2019) Besharat M.; Coronado Hernández, Óscar Enrique; Fuertes Miquel, Vicente S.; Viseu M.T.; Ramos H.M.
The occurrence of sub-atmospheric pressure in the drainage of pipelines containing an air pocket has been known as a major cause of several serious problems. Accordingly, some system malfunction and pipe buckling events have been reported in the literature. This case has been studied experimentally and numerically in the current research considering objectives for a better understanding of: (i) the emptying process, (ii) the main parameters influencing the drainage, and (iii) the air-water interface deformation. Also, this research demonstrates the ability of a computational fluid dynamic (CFD) model in the simulation of this event. The effects of the air pocket size, the percentage and the time of valve opening on the pressure variation have been studied. Results show the pipeline drainage mostly occurs due to backflow air intrusion. The worst case scenario is associated with a fast valve opening when a tiny air pocket exists in the pipeline. © 2019, © 2019 International Association for Hydro-Environment Engineering and Research.
Concerning Dynamic Effects in Pipe Systems with Two-Phase Flows: Pressure Surges, Cavitation, and Ventilation
(2022-07-31) Ramos, Helena M.; Fuertes Miquel, Vicente S.; Tasca, Elias; Coronado Hernández, Óscar Enrique; Besharat M.; Zhou, Ling; Karney, Bryan
The risks associated with unsteady two-phase flows in pressurized pipe systems must be considered both in system design and operation. To this end, this paper summarizes experimental tests and numerical analyses that highlight key aspects of unsteady two-phase flows in water pipelines. The essential dynamics of air–water interactions in unvented lines are first considered, followed by a summary of how system dynamics change when air venting is provided. System behaviour during unsteady two-phase flows is shown to be counter-intuitive, surprising, and complex. The role of air valves as protection devices is considered as is the reasonableness of the usual assumptions regarding air valve behaviour. The paper then numerically clarifies the relevance of cavitation and air valve performance to both the predicted air exchanges through any installed air valves and their role in modifying system behaviour during unsteady flows
Effect of a commercial air valve on the rapid filling of a single pipeline: A numerical and experimental analysis
(MDPI AG, 2019) Coronado Hernández, Óscar Enrique; Besharat M.; Fuertes Miquel, Vicente S.; Ramos H.M.
The filling process in water pipelines produces pressure surges caused by the compression of air pockets. In this sense, air valves should be appropriately designed to expel sufficient air to avoid pipeline failure. Recent studies concerning filling maneuvers have been addressed without considering the behavior of air valves. This work shows a mathematical model developed by the authors which is capable of simulating the main hydraulic and thermodynamic variables during filling operations under the effect of the air valve in a single pipeline, which is based on the mass oscillation equation, the air-water interface, the polytropic equation of the air phase, the air mass equation, and the air valve characterization. The mathematical model is validated in a 7.3-m-long pipeline with a 63-mm nominal diameter. A commercial air valve is positioned in the highest point of the hydraulic installation. Measurements indicate that the mathematical model can be used to simulate this phenomenon by providing good accuracy. © 2019 by the authors.
Effect of the non-stationarity of rainfall events on the design of hydraulic structures for runoff management and its applications to a case study at Gordo Creek watershed in Cartagena de Indias, Colombia
(MDPI AG, 2018) Gonzalez-Alvarez, A.; Coronado Hernández, Óscar Enrique; Fuertes Miquel, Vicente S.; Ramos, H.M.
The 24-h maximum rainfall (P 24h-max ) observations recorded at the synoptic weather station of Rafael Núñez airport (Cartagena de Indias, Colombia) were analyzed, and a linear increasing trend over time was identified. It was also noticed that the occurrence of the rainfall value (over the years of record) for a return period of 10 years under stationary conditions (148.1 mm) increased, which evidences a change in rainfall patterns. In these cases, the typical stationary frequency analysis is unable to capture such a change. So, in order to further evaluate rainfall observations, frequency analyses of P 24h-max for stationary and non-stationary conditions were carried out (by using the generalized extreme value distribution). The goodness-of-fit test of Akaike Information Criterion (AIC), with values of 753.3721 and 747.5103 for stationary and non-stationary conditions respectively, showed that the latter best depicts the increasing rainfall pattern. Values of rainfall were later estimated for different return periods (2, 5, 10, 25, 50, and 100 years) to quantify the increase (non-stationary versus stationary condition), which ranged 6% to 12% for return periods from 5 years to 100 years, and 44% for a 2-year return period. The effect of these findings were tested in the Gordo creek watershed by first calculating the resulting direct surface runoff (DSR) for various return periods, and then modeling the hydraulic behavior of the downstream area (composed of a 178.5-m creek's reach and an existing box-culvert located at the watershed outlet) that undergoes flooding events every year. The resulting DSR increase oscillated between 8% and 19% for return periods from 5 to 100 years, and 77% for a 2-year return period when the non-stationary and stationary scenarios were compared. The results of this study shed light upon to the precautions that designers should take when selecting a design, based upon rainfall observed, as it may result in an underestimation of both the direct surface runoff and the size of the hydraulic structures for runoff and flood management throughout the city. © 2018 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license.
Effects of orifice sizes for uncontrolled filling processes in water pipelines
(2022-03-12) Aguirre-Mendoza, Andres M.; Paternina-Verona, Duban A.; Oyuela, Sebastian; Coronado Hernández, Óscar Enrique; Besharat M.; Fuertes Miquel, Vicente S.; Iglesias-Rey P.L.; Ramos, Helena M.
The sizing of air valves during the air expulsion phase in rapid filling processes is crucial for design purposes. Mathematical models have been developed to simulate the behaviour of air valves during filling processes for air expulsion, utilising 1D and 2D schemes. These transient events involve the presence of two fluids with different properties and behaviours (water and air). The effect of air valves under scenarios of controlled filling processes has been studied by various authors; however, the analysis of uncontrolled filling processes using air valves has not yet been considered. In this scenario, water columns reach high velocities, causing part of them to close air valves, which generates an additional peak in air pocket pressure patterns. In this research, a two-dimensional computational fluid dynamics model is developed in OpenFOAM software to simulate the studied situations.
Emptying operation of water supply networks
(MDPI AG, 2017) Coronado Hernández, Óscar Enrique; Fuertes Miquel, Vicente S.; Angulo-Hernández, F.N.
Recently, emptying processes have been studied in experimental facilities in pipelines, but there is a lack regarding applications in actual pipelines, which permits establishing the risk of collapse because of sub-atmospheric pressure occurrence. This research presents a mathematical model to simulate the emptying process of water supply networks, and the application to a water emptying pipeline with nominal diameter of 1000 mm and 578 m long which is located on the southern of Cartagena, Bolívar Deparment, Colombia. In the application, both pipes and the air valve data manufacturer were considered. The behavior of all hydraulic and thermodynamic variables is considered. Results show that is crucial to know sub-atmospheric pressure values to prevent the collapse of the pipeline. The application of the mathematical model confirms that the hydraulic system is well designed depending on air valve sizes and maneuvering of drain valve. © 2018 by the authors.
Experimental and numerical analysis of a water emptying pipeline using different air valves
(MDPI AG, 2017) Coronado Hernández, Óscar Enrique; Fuertes Miquel, Vicente S.; Besharat M.; Ramos, H.M.
The emptying procedure is a common operation that engineers have to face in pipelines. This generates subatmospheric pressure caused by the expansion of air pockets, which can produce the collapse of the system depending on the conditions of the installation. To avoid this problem, engineers have to install air valves in pipelines. However, if air valves are not adequately designed, then the risk in pipelines continues. In this research, a mathematical model is developed to simulate an emptying process in pipelines that can be used for planning this type of operation. The one-dimensional proposed model analyzes the water phase propagation by a new rigid model and the air pockets effect using thermodynamic formulations. The proposed model is validated through measurements of the air pocket absolute pressure, the water velocity and the length of the emptying columns in an experimental facility. Results show that the proposed model can accurately predict the hydraulic characteristic variables. © 2017 by the authors.
Hydraulic modeling during filling and emptying processes in pressurized pipelines: a literature review
(Taylor and Francis Ltd., 2019) Fuertes Miquel, Vicente S.; Coronado Hernández, Óscar Enrique; Mora-Meliá D.; Iglesias-Rey P.L.
Filling and emptying processes are common maneuvers while operating, controlling and managing water pipeline systems. Currently, these operations are executed following recommendations from technical manuals and pipe manufacturers; however, these recommendations have a lack of understanding about the behavior of these processes. The application of mathematical models considering transient flows with entrapped air pockets is necessary because a rapid filling operation can cause pressure surges due to air pocket compressions, while an uncontrolled emptying operation can generate troughs of sub-atmospheric pressure caused by air pocket expansion. Depending on pipe and installation conditions, either situation can produce a rupture of pipe systems. Recently, reliable mathematical models have been developed by different researchers. This paper reviews and compares various mathematical models to simulate these processes. Water columns can be analyzed using a rigid water column model, an elastic water model, or 2D/3D CFD models; air–water interfaces using a piston-flow model or more complex models; air pockets through a polytropic model; and air valves using an isentropic nozzle flow or similar approaches. This work can be used as a starting point for planning filling and emptying operations in pressurized pipelines. Uncertainties of mathematical models of two-phases flow concerning to a non-variable friction factor, a polytropic coefficient, an air pocket sizes and an air valve behavior are identified. © 2019, © 2019 Informa UK Limited, trading as Taylor & Francis Group.
Maniobras de llenado y vaciado en grandes conducciones. Aplicación a una tubería de fundición DN400 en Massamagrell (Valencia, España)
(2020-01-31) Romero, G.; Coronado Hernández, Óscar Enrique; Fuertes Miquel, Vicente S.; Ponz-Carcelén, R.
Air pockets inside hydraulic installations during filling and emptying processes can generate pressure surges and negative pressure, respectively. Serious damages can be occurred in pipelines. In order to analyse hydraulic variables in filling and emptying operations, the selection of a mathematical model is chosen, which is suitable of simulating accurately the behaviour of both fluids (water and air) in pressurized water systems. The mathematical model proposed by the authors has been validated in small laboratory facilities. The aim of this work is to validate the mathematical model in current pipeline installations with large both nominal diameter and length. The pipeline is a nominal diameter DN400, and is located in Massamagrell, Valencia, Spain. The filling and emptying manoeuvres in the selected pipeline are performed by the Empresa Mixta Metropolitana S.A. (EMIMET). A good agreement is obtained when a comparison of absolute pressure and water flow is carried out between the mathematical model and the measurements.
Quasi-static flow model for predicting the extreme values of air pocket pressure in draining and filling operations in single water installations
(2020) Coronado Hernández, Óscar Enrique; Fuertes Miquel, Vicente S.; Mora-Meliá, Daniel; Salgueiro, Yamisleydi
Inertial models have been used by researchers to simulate the draining and filling processes in water pipelines, based on the evolution of the main hydraulic and thermodynamic variables. These models use complex differential equations, which are solved using advanced numerical codes. In this study, a quasi-static flow model is developed to study these operations in hydraulic installations. The quasi-static flow model represents a simplified formulation compared with inertial flow models, in which its numerical resolution is easier because only algebraic equations must be addressed. Experimental measurements of air pocket pressure patterns were conducted in a 4.36 m long single pipeline with an internal diameter of 42 mm. Comparisons between measured and computed air pocket pressure oscillations indicate how the quasi-static flow model can predict extreme values of air pocket pressure for experimental runs, demonstrating the possibility of selecting stiffness and pipe classes in actual pipelines using this model. Two case studies were analysed to determine the behaviour of the quasi-static flow model in large water pipelines.
Rigid water column model for simulating the emptying process in a pipeline using pressurized air
(American Society of Civil Engineers (ASCE), 2018) Coronado Hernández, Óscar Enrique; Fuertes Miquel, Vicente S.; Iglesias-Rey P.L.; Martínez-Solano F.J.
This paper presents a mathematical model for analyzing the emptying process in a pipeline using pressurized air. The rigid water column model (RWCM) is used to analyze the transient phenomena that occur during the emptying of the pipeline. The air-water interface is also computed in the proposed model. The proposed model is applied along a 271.6-m-long PVC-steel pipeline with a 232-mm internal diameter. The boundary conditions are given by a high-pressure air tank at the upstream end and a manual butterfly valve at the downstream end. The solution was carried out in a computer modeling program. The results show that comparisons between both the computed and measured water flow oscillations and gauge pressures are very similar; hence, the model can effectively simulate the transient flow in this system. In addition, the results indicate that the proposed model can predict both the water flow and gauge pressure better than previous models. © 2018 American Society of Civil Engineers.
Simplified mathematical model for computing draining operations in pipelines of undulating profiles with vacuum air valves
(2020-09-11) Coronado Hernández, Óscar Enrique; Fuertes Miquel, Vicente S.; Quiñones-Bolaños, Edgar Eduardo; Gatica, Gustavo; Coronado Hernández, Jairo Rafael
The draining operation involves the presence of entrapped air pockets, which are expanded during the phenomenon occurrence generating drops of sub-atmospheric pressure pulses. Vacuum air valves should inject enough air to prevent sub-atmospheric pressure conditions. Recently, this phenomenon has been studied by the authors with an inertial model, obtaining a complex formulation based on a system composed by algebraic-differential equations. This research simplifies this complex formulation by neglecting the inertial term, thus the Bernoulli’s equation can be used. Results show how the inertial model and the simplified mathematical model provide similar results of the evolution of main hydraulic and thermodynamic variables. The simplified mathematical model is also verified using experimental tests of air pocket pressure, water velocity, and position of the water column