The motion of entrapped air cavities in inclined ducts

Bashiri-Atrabi, Hamid; Hosoda, Toru

doi:10.1080/00221686.2015.1060272

Cited by 8 publications

(3 citation statements)

References 11 publications

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“…Zhou et al 17 experimentally investigated the transient flow characteristics of horizontal pipes containing trapped air during a rapid filling process. Atrabi et al 18 also studied the motion regularities of entrapped air cavities in an inclined pipe. In addition, the hydraulic characteristics of different drop shafts were experimentally investigated by some scholars 19 – 21 .…”

Section: Introductionmentioning

confidence: 99%

Experimental investigation on the hazard of geyser created by an entrapped air release in baffle-drop shafts

Yang

Qian²

2023

Sci Rep

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The geyser phenomenon seriously threatens the safe operation of deep tunnel drainage systems and drop shaft structural safety. To simulate the geyser process in a baffle-drop shaft, a 1:50 scale model test system was used to research the response relationship between the geyser mechanism and test parameters such as water depth, inlet pressure, and inlet volume. The results show that the pressure in a baffle-drop shaft fluctuates sharply during the geyser process. This is caused by the release of a high-pressure air mass, and high-speed movement of the air–water mixture causes a local pressure imbalance in the drop shaft. A prediction formula for the maximum geyser height of a baffle-drop shaft was established by a multiple linear regression model. Geyser occurrence conditions for the baffle-drop shaft were proposed combined with the response relationship between different influence variables and geyser intensity. Except for the inlet pressure, submerged state of the baffles, and measured location, the hydrodynamic load on the bottom of the baffles is also related to the randomness of the air–water mixture jetted on the baffle bottom. The maximum hydrodynamic load on the baffle bottom during the geyser is 10 times the hydrodynamic load on the baffle surface under normal discharge conditions. This research provides a theoretical reference for the structural design and safe operation of baffle-drop shafts.

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Section: Introductionmentioning

confidence: 99%

Experimental investigation on the hazard of geyser created by an entrapped air release in baffle-drop shafts

Yang

Qian²

2023

Sci Rep

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“…When the pipeline empties, the air pocket expands and generates a vacuum that causes a pressure drop [4]. The presence of two fluids (water and air) introduces greater complexity in the analysis of transient phenomena that occur during emptying processes [4], since it is necessary to use a hydraulic (water column) and thermodynamic (trapped air pocket) approach [5][6][7][8].…”

Section: Introductionmentioning

confidence: 99%

Transient Phenomena Generated in Emptying Operations in Large-Scale Hydraulic Pipelines

Romero¹,

Fuertes-Miquel

Coronado-Hernández

et al. 2020

Water

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Air pockets generated during emptying operations in pressurized hydraulic systems cause significant pressure drops inside pipes. To avoid these sudden pressure changes, one of the most widely used methods involves the installation of air valves along the pipeline route. These elements allow air exchange between the exterior and the interior of the pipe, which alleviates the pressure drops produced and thus prevents possible breaks or failures in the structure of the installation. This study uses a mathematical model previously validated by the authors in smaller installations to simulate all hydraulic variables involved in emptying processes over time. The purpose of these simulations is the validation of the mathematical model in real large-scale installations, and to do this, the results obtained with the mathematical model are compared with actual measurements made by the partner company. The hydraulic system selected for the study is a pipeline with a nominal diameter of 400 mm and a total length of 1020 m. The results obtained from the mathematical model show great similarity with the experimental measurements, thus validating the model for emptying large pipes.

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“…Additionally, a few pieces of research have been published analyzing the influence of different parameters through experimental investigations of the systems (Hou et al, 2014;Zhou & Liu, 2013).Finally, others studies have focused on techniques and methods for solving the filling problem (Liu, Zhou, Karney, Zhang, & Ou, 2011;Malekpour & Karney, 2014;Martins, Ramos, & Almeida, 2010;Martins et al, 2015;H. Wang et al, 2016), analyzing the consequences of the formation of air pockets (Pozos, González, Giesecke, Marx, & Rodal, 2010), and the occurrence of cavitation in the propagation of transient phenomena (Bashiri-Atrabi & Hosoda, 2015;Guinot, 2001;K. Wang, Shen, & Zhang, 2003).…”

Section: Introductionmentioning

confidence: 99%

Transient phenomena during the emptying process of a single pipe with water–air interaction

Fuertes-Miquel

Coronado-Hernández

Iglesias-Rey

et al. 2018

Journal of Hydraulic Research

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The motion of entrapped air cavities in inclined ducts

Cited by 8 publications

References 11 publications

Experimental investigation on the hazard of geyser created by an entrapped air release in baffle-drop shafts

Experimental investigation on the hazard of geyser created by an entrapped air release in baffle-drop shafts

Transient Phenomena Generated in Emptying Operations in Large-Scale Hydraulic Pipelines

Transient phenomena during the emptying process of a single pipe with water–air interaction

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