Investigation of Hydraulic Transients of Two Entrapped Air Pockets in a Water Pipeline

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

doi:10.1061/(asce)hy.1943-7900.0000750

Cited by 89 publications

(75 citation statements)

References 8 publications

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“…This problem can be studied using one (1D) [10,11], two (2D) [12] or three-dimensional (3D) [13] models. The water phase in the 1D model can be analyzed considering two types of models [14]: (i) elastic models [15,16], which consider the elasticity of the pipe and the water; or (ii) rigid models [17], which ignore the elasticity of them.…”

Section: Introductionmentioning

confidence: 99%

“…Normally, elastic models are solved by using the method of characteristics [18,19] and rigid models by using the numerical solutions of ordinary differential equations [3,11,17,20]. In pressurized systems, the air effect can be analyzed as a single-phase flow, where the absolute pressure of the air pocket is computed between two water columns [10,11,21]. Regarding the analysis of 2D and 3D CFD modeling of air-water interface in closed pipes, they are still unyielding in the application of pipeline draining because length and time scales are not appropriate.…”

Section: Introductionmentioning

confidence: 99%

“…This research develops a general 1D mathematical model that can be used for analyzing the behaviour of the main hydraulic variables during the emptying process in a pipeline with an irregular profile and with several air valves installed along it based on formulations of previous works [3,10,11,17,20,22,23]. The proposed model can give important information in real systems about: (i) the risk of collapse of pipeline installations, by checking in a pipe manufacturer characteristics if the stiffness class is appropriate to support the subatmospheric pressure reached during the hydraulic event depending on the type of soil in natural conditions, the type of backfill and the cover depth; (ii) the appropriate selection of the air valve during the emptying process; (iii) the size and the maneuver time of the drain valves; and (iv) the estimation of the drainage time of a pipeline.…”

Section: Introductionmentioning

confidence: 99%

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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: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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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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“…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%

“…They found that the maximum peak pressure of the air pocket first increased and then decreased with decreasing void fraction. For the filling of pipelines with undulating profile, multiple air pockets and an open end, the rapid compression of the entrapped air may cause huge pressures (Cabrera et al 1997, Izquierdo et al 1999, Zhou et al 2013a). When two air pockets are entrapped, the case with similar sizes was the most complicated and dangerous one (Zhou et al 2013a).…”

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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Numerical calculation of air entrainment rates due to intake vortices

Sarkardeh

2017

Meccanica

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Investigation of Hydraulic Transients of Two Entrapped Air Pockets in a Water Pipeline

Cited by 89 publications

References 8 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

Numerical calculation of air entrainment rates due to intake vortices

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