Influence of Liquid Length Variation in Hydraulic Transients

Cabrera, Enrique; Abreu, J.; Pérez, Rafael Sirera; Vela, Antonio

doi:10.1061/(asce)0733-9429(1992)118:12(1639)

Cited by 54 publications

(35 citation statements)

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“…The rigid model was used in order to compute the evolution of the water column [11,25], considering that the elasticity of the air is much higher than the elasticity of the pipe and the water [12]. Applying the rigid model to the emptying column j and considering that the drain valve s joins pipes L j and L j−1 , which is a common point in a pipeline, then:…”

Section: Equations For the Water Phasementioning

confidence: 99%

Experimental and Numerical Analysis of a Water Emptying Pipeline Using Different Air Valves

Coronado-Hernández

Fuertes-Miquel

Besharat

et al. 2017

Water

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Abstract: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.

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Section: Equations For the Water Phasementioning

confidence: 99%

Experimental and Numerical Analysis of a Water Emptying Pipeline Using Different Air Valves

Coronado-Hernández

Fuertes-Miquel

Besharat

et al. 2017

Water

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“…To model rapid filling of pipelines with initially entrapped air, end orifice or ventilation conditions, many researchers have applied rigid-column theory (Cabrera et al 1992, Liou and Hunt 1996, Cabrera et al 1997, Izquierdo et al 1999, Trajkovic et al 1999, Lee and Martin 1999, Zhou 2000, Liu and Suo 2004, Martin and Lee 2012 and developed other sophisticated mathematical models and corresponding numerical techniques , Lee 2005, Zhou et al 2011, Hou et al 2012b, Zhou et al 2013a, Zhou et al 2013b, Trindade and Vasconcelos 2013. While the primary objective of this paper is to present the experimental results, the potential significance of these can be illustrated by comparison with the existing state of the art in the modelling of rapid pipe filling.…”

Section: Numerical Simulationmentioning

confidence: 99%

“…In the context of pipe filling, the usual focus was on physical factors affecting the peak transient pressure, such as the location and size of entrapped air pocket(s), the water column length, the driving pressure head and the size of the end orifice (Martin 1976, Ocasio 1976, Cabrera et al 1992, Cabrera et al 1997, Izquierdo et al 1999, Lee and Martin 1999, Zhou 2000, Liu and Suo 2004, Lee 2005, De Martino et al 2008, Zhou et al 2011, Martin and Lee 2012, Zhou et al 2013a, Zhou et al 2013b). Ocasio (1976) carried out experiments with entrapped air pockets at a dead end and demonstrated that the presence of entrapped air could result in destructive pressure surges.…”

Section: Introductionmentioning

confidence: 99%

Experimental Investigation on Rapid Filling of a Large-Scale Pipeline

et al. 2014

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Document VersionPublisher's PDF, also known as Version of Record (includes final page, issue and volume numbers) Please check the document version of this publication:• A submitted manuscript is the author's version of the article upon submission and before peer-review. There can be important differences between the submitted version and the official published version of record. People interested in the research are advised to contact the author for the final version of the publication, or visit the DOI to the publisher's website.• The final author version and the galley proof are versions of the publication after peer review.• The final published version features the final layout of the paper including the volume, issue and page numbers. Link to publication General rightsCopyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.• Users may download and print one copy of any publication from the public portal for the purpose of private study or research.• You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal ? Take down policyIf you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. ABSTRACTThis study presents results from detailed experiments of the two-phase pressurized flow behavior during the rapid filling of a large-scale pipeline. The physical scale of this experiment is close to the practical situation in many industrial plants. Pressure transducers, water level meters, thermometers, void fraction meters and flow meters were used to measure the two-phase unsteady flow dynamics. The main focus is on the water-air interface evolution during filling and the overall behavior of the lengthening water column. It is observed that the leading liquid front does not entirely fill the pipe cross section; flow stratification and mixing occurs. Although flow regime transition is a rather complex phenomenon, certain features of the observed transition pattern are explained qualitatively and quantitatively. The water flow during the entire filling behaves as a rigid column as the open empty pipe in front of the water column provides sufficient room for the water column to occupy without invoking air compressibility effects. As a preliminary evaluation of how these large-scale experiments can feed into improving mathematical modeling of rapid pipe filling, a comparison with a typical one-dimensional rigid-column model is made.

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“…High pressure surge originates at the end of the filling phase, because of the impact of the liquid column on the valve, after the air has been expelled, due to the difference in density between air and water [2,3]. On the other hand, the presence of air can be beneficial in some conditions because of the cushioning effect of the air pocket, which operates as an air chamber, especially during the transient first phase.…”

Section: Introductionmentioning

confidence: 99%

Hydraulic Transients Caused by Air Expulsion During Rapid Filling of Undulating Pipelines

Apollonio

Balacco

Fontana

et al. 2016

Water

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Abstract:One of the main issues arising during the rapid filling of a pipeline is the pressure transient which originates after the entrapped air has been expelled at the air release valve. Because of the difference in density between water and air, a pressure transient originates at the impact of the water column. Many authors have analyzed the problem, both from the theoretical and the experimental standpoint. Nevertheless, mainly vertical or horizontal pipelines have been analyzed, whereas in real field applications, the pipe profile is a sequence of ascending and descending pipes, with air release/vacuum valves at high points. To overcome lack of knowledge regarding this latter case, laboratory experiments were carried out to simulate the filling of an undulating pipeline, initially empty at atmospheric pressure. The pipe profile has a high point where an orifice is installed for air venting, so as to simulate the air release valve at intermediate high point of a supply pipeline. In the experiments, the diameter of the orifice and the opening degree of both upstream and downstream valves were varied, in order to analyze their effect on the pressure transient. The experiments were also carried out with a longer descending pipe, in order to assess the effects on the pressure surge of the air volume downstream of the orifice.

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Influence of Liquid Length Variation in Hydraulic Transients

Cited by 54 publications

References 0 publications

Experimental and Numerical Analysis of a Water Emptying Pipeline Using Different Air Valves

Experimental and Numerical Analysis of a Water Emptying Pipeline Using Different Air Valves

Experimental Investigation on Rapid Filling of a Large-Scale Pipeline

Hydraulic Transients Caused by Air Expulsion During Rapid Filling of Undulating Pipelines

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