Physical Understanding of Sudden Pressurization of Pipe Systems with Entrapped Air: Energy Auditing Approach

Malekpour, Ahmad; Karney, Bryan W.; Nault, J. D.

doi:10.1061/(asce)hy.1943-7900.0001067

Cited by 26 publications

(16 citation statements)

References 14 publications

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“…Because the movement of the liquid column can be studied without considering the elastic effects (Liu and Hunt 1996;Li and McCorquodale 1999;Fuertes 2001;Zhou et al 2002;Vasconcelos and Leite 2012;Malekpour et al 2016), the equations that model the behaviour of the system are as follows:…”

Section: Mathematical Modelmentioning

confidence: 99%

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: Mathematical Modelmentioning

confidence: 99%

Numerical modelling of pipelines with air pockets and air valves

et al. 2016

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“…The filling process is capable of inducing very huge spikes of pressure that can lead to damage to the pipeline equipment or eventually induce a pipe rupture. Previous studies have focused on different aspects of the filling process under different conditions [19][20][21][22][23]. The thermodynamic behavior of the system plays a significant role in the transient phenomena.…”

Section: Introductionmentioning

confidence: 99%

Effect of a Commercial Air Valve on the Rapid Filling of a Single Pipeline: a Numerical and Experimental Analysis

Coronado-Hernández

Besharat

Fuertes-Miquel

et al. 2019

Water

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The filling process in water pipelines produces pressure surges caused by the compression of air pockets. In this sense, air valves should be appropriately designed to expel sufficient air to avoid pipeline failure. Recent studies concerning filling maneuvers have been addressed without considering the behavior of air valves. This work shows a mathematical model developed by the authors which is capable of simulating the main hydraulic and thermodynamic variables during filling operations under the effect of the air valve in a single pipeline, which is based on the mass oscillation equation, the air-water interface, the polytropic equation of the air phase, the air mass equation, and the air valve characterization. The mathematical model is validated in a 7.3-m-long pipeline with a 63-mm nominal diameter. A commercial air valve is positioned in the highest point of the hydraulic installation. Measurements indicate that the mathematical model can be used to simulate this phenomenon by providing good accuracy.

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“…• The air-water interface is simulated using a piston flow model [2,16]. Sections 2.1 and 2.2 present the mathematical formulations of the draining and filling processes using the quasi-static flow model, respectively.…”

Section: Draining Processmentioning

confidence: 99%

“…Recently, draining and filling processes have been investigated using inertial models for the water phase [14,15] and a polytropic law for the air phase [5,8]. Some researchers have used elastic models, where the elasticities of water and pipe have been considered [4,16], and others have used rigid column models to simulate the water phase because the elasticity of air is much higher compared to those of water and pipes [2,7]. Inertial models have been validated in several experimental setups and demonstrated that both models presented a good agreement regarding experimental tests [7,9].…”

Section: Introductionmentioning

confidence: 99%

Quasi-static Flow Model for Predicting the Extreme Values of Air Pocket Pressure in Draining and Filling Operations in Single Water Installations

Coronado-Hernández

Fuertes-Miquel

Mora-Meliá

et al. 2020

Water

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Inertial models have been used by researchers to simulate the draining and filling processes in water pipelines, based on the evolution of the main hydraulic and thermodynamic variables. These models use complex differential equations, which are solved using advanced numerical codes. In this study, a quasi-static flow model is developed to study these operations in hydraulic installations. The quasi-static flow model represents a simplified formulation compared with inertial flow models, in which its numerical resolution is easier because only algebraic equations must be addressed. Experimental measurements of air pocket pressure patterns were conducted in a 4.36 m long single pipeline with an internal diameter of 42 mm. Comparisons between measured and computed air pocket pressure oscillations indicate how the quasi-static flow model can predict extreme values of air pocket pressure for experimental runs, demonstrating the possibility of selecting stiffness and pipe classes in actual pipelines using this model. Two case studies were analysed to determine the behaviour of the quasi-static flow model in large water pipelines.

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Physical Understanding of Sudden Pressurization of Pipe Systems with Entrapped Air: Energy Auditing Approach

Cited by 26 publications

References 14 publications

Numerical modelling of pipelines with air pockets and air valves

Numerical modelling of pipelines with air pockets and air valves

Effect of a Commercial Air Valve on the Rapid Filling of a Single Pipeline: a Numerical and Experimental Analysis

Quasi-static Flow Model for Predicting the Extreme Values of Air Pocket Pressure in Draining and Filling Operations in Single Water Installations

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