Phenomenon of White Mist in Pipelines Rapidly Filling with Water with Entrapped Air Pockets

Zhou, Ling; Liu, Deyou; Karney, Bryan W.; Wang, Pei

doi:10.1061/(asce)hy.1943-7900.0000765

Cited by 56 publications

(46 citation statements)

References 8 publications

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“…Thus, some authors propose an isothermal evolution (Almeida and Koelle 1992;De Martino et al 2008;Trindade and Vasconcelos 2013;Bousso and Fuamba, 2014), while other authors propose an adiabatic evolution (Lee and Martin 1999;Zhou et al 2002;Zhou et al 2004;Martins et al 2009;Vasconcelos and Wright 2011;Liu et al 2011;Zhou et al 2011;Zhou et al 2013a;Zhou et al 2013b) or intermediate values such as n = 1.2 (Martin 1976;Jönsson 1985;Li and McCorquodale 1999;Pozos et al 2010b;Carlos et al 2011;Vasconcelos and Leite 2012) or n = 1.3 (Thorley and Spurrett 1989). In fact, the polytrophic coefficient value depends on the thermal characteristics of the system and how fast the transient occurs and most likely varies during the transient.…”

Section: R a F Tmentioning

confidence: 99%

“…Other authors use different model approaches, such as a model based on the SaintVenant modified equations (Vasconcelos et al 2006;Vasconcelos and Wright 2009;Trindade and Vasconcelos 2013), using finite volume models (León et al 2008;León et al 2010), or applying the method of characteristics (Martins et al 2009;Pozos et al 2010b;Carlos et al 2011;Zhou et al 2011;Zhou et al 2013a;Zhou et al 2013b). Each model has its strengths and limitations (Bousso et al 2013).…”

Section: R a F Tmentioning

confidence: 99%

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Numerical modelling of pipelines with air pockets and air valves

et al. 2016

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This work considers the behaviour of air inside pipes when the air is expelled through air valves. Generally, the air shows isothermal behaviour. Nevertheless, when the transient is very fast, it shows adiabatic behaviour. In a real installation, an intermediate evolution between these two extreme conditions occurs. Thus, it is verified that the results vary significantly depending on the hypothesis adopted. To determine the pressure of the air pocket, the most unfavourable hypothesis (isothermal behaviour) is typically adopted.Nevertheless, from the perspective of the water hammer that takes place when the water column arrives at the air valve and abruptly closes, the most unfavourable hypothesis is the opposite (adiabatic behaviour). In this case, the residual velocity with which the water arrives at the air valve is higher, and, consequently, the water hammer generated is greater.

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Section: R a F Tmentioning

confidence: 99%

Section: R a F Tmentioning

confidence: 99%

Numerical modelling of pipelines with air pockets and air valves

et al. 2016

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“…The position of the air-water interface is considered perpendicular to the pipe direction [11,18,26]. The continuity equation for the moving air-water interface j is:…”

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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“…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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Phenomenon of White Mist in Pipelines Rapidly Filling with Water with Entrapped Air Pockets

Cited by 56 publications

References 8 publications

Numerical modelling of pipelines with air pockets and air valves

Numerical modelling of pipelines with air pockets and 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

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