Emptying Operation of Water Supply Networks

Coronado-Hernández, Óscar E.; Fuertes-Miquel, Vicente S.; Angulo-Hernandez, Fredy N.

doi:10.3390/w10010022

Cited by 10 publications

(9 citation statements)

References 16 publications

(33 reference statements)

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“…P t+ t l = P t+ t pigb (10) In which: P pig , P g , P l -the pressure of the pig, gas, liquid, Pa. If the pig does not move to the next node of the grid, that is, at a position between the two nodes (FIGURE 4), then the speed of point p can be obtained by the following difference formula:…”

Section: A Mathematical Modelmentioning

confidence: 99%

Simulation Model and Case Study of Drainage Process After Pressure Test of Large Drop Natural Gas Pipeline

Liu

Peng

et al. 2020

IEEE Access

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The drainage process of a large drop natural gas pipeline after a pressure test is a complicated transient flow process. This process is a gas-phase and liquid-phase flow process connected by a pig, in which the pressure inside the tube, and the flow velocity of gas and liquid, and the movement state of the pig are constantly changing. At the same time, there are also a variety of complicated working conditions such as liquid evaporation and water hammer. Based on the pig transient model, a transient simulation model is established for the upstream gas section and downstream liquid sections of the pipeline in this paper, and the discrete vapor cavity model is used to simulate the drainage process. Taking a large drop pipe section of natural gas pipeline as an example, the paper studied the influences of key parameters such as flow velocity and pressure on the inlet and outlet of the pipeline on the drainage process and analyzed the complicated conditions such as discrete cavity and water hammer in the pipeline during the drainage process. In this paper, the law of pressure variation in the pipe is obtained, and the method of adjusting the inlet and outlet pressure and flow velocity of the pipe section by segmentation is proposed to avoid the occurrence of complex working conditions such as discrete cavity and water hammer. INDEX TERMS Pig, large drop, drainage, transient flow, numerical simulation, water hammer.

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Section: A Mathematical Modelmentioning

confidence: 99%

Simulation Model and Case Study of Drainage Process After Pressure Test of Large Drop Natural Gas Pipeline

Liu

Peng

et al. 2020

IEEE Access

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“…Sin embargo, el análisis de los fenómenos transitorios durante las operaciones de vaciado de los sistemas hidráulicos ha sido poco estudiado hasta el momento actual. Los autores han desarrollaron un modelo matemático robusto que permite conocer dicho comportamiento (Coronado-Hernández et al, 2017b;Fuertes-Miquel et al, 2017), el cual ha sido validado en los laboratorios de la Universitat Politècnica de València (España), para el caso de una tubería simple; y de la Universidad de Lisboa (Portugal), para el caso de una conducción de perfil irregular.…”

Section: Introductionunclassified

“…Sin embargo, en las instalaciones reales suele producirse una situación intermedia (hay cambio de temperatura y hay transferencia de calor). En estos casos se suele adoptar un valor intermedio para el coeficiente politrópico, por ejemplo m = 1.2 (Coronado-Hernández et al, 2017b).…”

Section: Introductionunclassified

“…En conducciones reales se deberá verificar el riesgo de colapso por las depresiones que pueden ocurrir durante el vaciado de agua, analizando si la rigidez de la tubería (suministrada por el fabricante) es suficiente para resistir la depresión dependiendo de las condiciones de instalación de la conducción (el tipo de relleno, la clase de suelo y la profundidad de instalación), tal como se presenta en el trabajo desarrollado por los autores (Coronado-Hernández et al, 2017b).…”

Section: Introductionunclassified

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Parámetros significativos durante los procesos de vaciado en conducciones de agua

et al. 2018

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RESUMENEl proceso de vaciado en conducciones de agua genera depresiones por la expansión del aire en el interior de las tuberías y esto podría causar el colapso del sistema dependiendo de las condiciones de instalación y de la rigidez de la conducción. En este artículo se presenta el análisis de sensibilidad del modelo matemático desarrollado por los autores, analizando los principales parámetros hidráulicos y termodinámicos que intervienen en este proceso tales como: diámetro interior de la tubería, factor de fricción, pendiente longitudinal de la tubería, coeficiente politrópico, diámetro de la ventosa, tamaño de la bolsa de aire y tiempo de apertura. Este análisis se realizó para dos casos posibles: Caso No. 1, tubería con el extremo aguas arriba cerrado; y Caso No. 2, tubería con una ventosa instalada en el extremo aguas arriba. Los resultados muestran que para el Caso No. 1 los parámetros que más inciden en las depresiones son la pendiente longitudinal de la tubería, el coeficiente politrópico y el tamaño de la bolsa de aire; mientras que para el Caso No. 2, la mayoría de los parámetros influyen significativamente durante el proceso de vaciado.Palabras clave | válvulas de aire; interfaz aire-agua; vaciado; análisis de sensibilidad; fenómenos transitorios; redes de abastecimiento de agua. ABSTRACT

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“…For instance, the bulk modulus in an isothermal process, at atmospheric condition, presents a ratio of 20000 times, and for an absolute pressure of 10 bar, the ratio is of 2000 times. Some of the problems cause by entrapped air pockets are: (i) additional head losses by increasing the water velocity as a consequence of the reduction of the cross section (Stephenson, 1997), (ii) pressure surges for starting or stopping the system because of the compression of the air pocket, (iii) reduction of the efficiency of the pumps, (iv) vibrations in pipelines, which generate rapid changes in the water velocity pattern, (iv) pipe corrosion owing to temperature and absolute pressure changes, and (v) troughs of subatmospheric pressure by the expansion of the air pocket Coronado-Hernández et al, 2018a).…”

Section: Introductionmentioning

confidence: 99%

Transient phenomena during the emptying process of water in pressurized pipelines

Hernández¹,

Enrique²

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AgradecimientosQuiero agradecer al Dr. Vicente Samuel Fuertes-Miquel por haber sido mi director de tesis doctoral, en donde sentí su apoyo desde que inicié estos estudios en la Universitat Politècnica de València. También deseo agradecer a la Prof. Helena M. Ramos por su ayuda durante la estancia de investigación en la Universidad de Lisboa (Portugal).Gracias al apoyo incondicional de mi amada esposa Claudia Milena, quien estuvo conmigo durante todo este proceso apoyándome constantemente y motivándome a finalizar mis estudios de doctorado, y por supuesto a mi bebé Salomón por haberme cambiado la vida durante este proceso. De igual manera estoy muy agradecido por el amor de Mami Delcy, de hermani (Jairo Rafael) y de mi padre Jairo de Jesús (QEPD).Gracias al Dios Triuno (Padre, Hijo y Espíritu) por haberme brindado la capacidad para afrontar y terminar este reto. Valencia (España), Enero de 2019V This page is intentionally left blank. --VI AbstractThe analysis of transient phenomena during water filling operations in pipelines of irregular profiles has been studied much more compared to emptying maneuvers. In the literature, there is a lack of knowledge about mathematical models of emptying operations. This research starts with the analysis of a transient phenomenon during emptying maneuvers in single pipelines, which is a previous stage to understand the emptying operation in pipelines of irregular profiles. Analysis are conducted under two typical situations: (i) one corresponding to either the situation where there are no air valves installed or when they have failed due to operational and maintenance problems which represents the worse condition due to causing the lowest troughs of subatmospheric pressure, and (ii) the other one corresponding to the situation where air valves have been installed at the highest point of hydraulic installations to give reliability by admitting air into the pipelines for preventing troughs of subatmospheric pressure. Particularly, this research developed a mathematical model to predict the behavior of the emptying operations. The mathematical model is proposed for the two aforementioned situations. The liquid phase (water) is simulated using a rigid water column model (RWCM), which neglects the pipe and water elasticity given that the elasticity of the entrapped air pockets is much higher than the one from the pipe and the water. The air-water interface is simulated with a piston flow model assuming that the water column is perpendicular with the main direction of the flow. Gas phase is modeled using three formulations: (a) a polytropic model based on its energetic behavior, which considers an expansion of air pockets; (b) an air valve characterization to quantify the magnitude of admitted air flow; and (c) a continuity equation of the air. An ordinary differential equations system is solved using the Simulink tool of Matlab.The proposed model has been validated using experimental facilities at the hydraulic laboratories of the Universitat Politècnica de València, Valencia, Spain,...

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Emptying Operation of Water Supply Networks

Cited by 10 publications

References 16 publications

Simulation Model and Case Study of Drainage Process After Pressure Test of Large Drop Natural Gas Pipeline

Simulation Model and Case Study of Drainage Process After Pressure Test of Large Drop Natural Gas Pipeline

Parámetros significativos durante los procesos de vaciado en conducciones de agua

Transient phenomena during the emptying process of water in pressurized pipelines

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