Numerical modelling of pipelines with air pockets and air valves

Fuertes-Miquel, Vicente S.; Jiménez, Petra Amparo López; Martínez-Solano, F. Javier; López-Patiño, Gonzalo

doi:10.1139/cjce-2016-0209

Cited by 30 publications

(39 citation statements)

References 27 publications

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“…The mathematical model uses the following formulations: (i) rigid model to represent the water phase behavior [3,5,15,20]; (ii) a piston flow to describe the air-water interface [3][4][5]21]; (iii) a polytropic equation to describe the air phase behavior [22][23][24]; (iv) the continuity equation of the air pocket [5,15]; and (v) the air valve characterization [13] to quantify the admitted air volume.…”

Section: Application Of the Mathematical Modelmentioning

confidence: 99%

Emptying Operation of Water Supply Networks

Coronado-Hernández

Fuertes-Miquel

Angulo-Hernandez³

2017

Water

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Abstract: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.

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Section: Application Of the Mathematical Modelmentioning

confidence: 99%

Emptying Operation of Water Supply Networks

Coronado-Hernández

Fuertes-Miquel

Angulo-Hernandez³

2017

Water

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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. 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].…”

Section: Introductionmentioning

confidence: 99%

“…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. 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].…”

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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“…Iglesias-Rey et al [23] performed a detailed study of the actual behavior of different valves (both air intake and exhaust) and described the mathematical characterization of different commercial valves. Fuertes-Miquel et al [24] presented a numerical modeling of pipelines with air pockets and air valves to study the behavior of the air inside pipes as the air was expelled through air valves. Majd et al [25] investigated the unsteady flow of a non-Newtonian fluid due to the instantaneous valve closure in a pipeline.…”

Section: Introductionmentioning

confidence: 99%

Pressure Transient Model of Water-Hydraulic Pipelines with Cavitation

Jiang¹,

Ren²,

Zhao³

et al. 2018

Applied Sciences

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Transient pressure investigation of water-hydraulic pipelines is a challenge in the fluid transmission field, since the flow continuity equation and momentum equation are partial differential, and the vaporous cavitation has high dynamics; the frictional force caused by fluid viscosity is especially uncertain. In this study, due to the different transient pressure dynamics in upstream and downstream pipelines, the finite difference method (FDM) is adopted to handle pressure transients with and without cavitation, as well as steady friction and frequency-dependent unsteady friction. Different from the traditional method of characteristics (MOC), the FDM is advantageous in terms of the simple and convenient computation. Furthermore, the mechanism of cavitation growth and collapse are captured both upstream and downstream of the water-hydraulic pipeline, i.e., the cavitation start time, the end time, the duration, the maximum volume, and the corresponding time points. By referring to the experimental results of two previous works, the comparative simulation results of two computation methods are verified in experimental water-hydraulic pipelines, which indicates that the finite difference method shows better data consistency than the MOC.

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Numerical modelling of pipelines with air pockets and air valves

Cited by 30 publications

References 27 publications

Emptying Operation of Water Supply Networks

Emptying Operation of Water Supply Networks

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

Pressure Transient Model of Water-Hydraulic Pipelines with Cavitation

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