Air entrapped in gravity pipeline systems

Pozos, Oscar; Gonzalez, Carlos A.; Giesecke, Juergen; Marx, W.; Rodal, E

doi:10.1080/00221686.2010.481839

Cited by 47 publications

(37 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Furthermore, most of the wires exhibited little corrosion whilst the cylinder showed only superficial corrosion, as shown in Figure 1. Pozos et al [22] was used to identify the location of the air pockets in the pipeline and their volume was computed with a relationship based on the theory of the gradually varied flow. A detail survey of the pipeline was performed using a combination of non-destructive technologies in order to determine if immediate intervention was required to replace PCC pipes.…”

Section: Pipeline Accidentmentioning

confidence: 99%

“…In order to fully validate the diagnostic and to investigate the destructive effect of air pockets on surge pressures in the system, a hydraulic transient analysis with entrapped air in the pumping pipeline was carried out. The methodology suggested by Pozos et al [22] was used to identify the location of the air pockets in the pipeline and their volume was computed with a relationship based on the theory of the gradually varied flow. A detail survey of the pipeline was performed using a combination of non-destructive technologies in order to determine if immediate intervention was required to replace PCC pipes.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Failure Analysis of a Water Supply Pumping Pipeline System

Pozos‐Estrada

Sánchez-Huerta

Breña-Naranjo

et al. 2016

Water

View full text Add to dashboard Cite

This paper describes the most important results of a theoretical, experimental and in situ investigation developed in connection with a water supply pumping pipeline failure. This incident occurred after power failure of the pumping system that caused the burst of a prestressed concrete cylinder pipe (PCCP). Subsequently, numerous hydraulic transient simulations for different scenarios and various air pockets combinations were carried out in order to fully validate the diagnostic. As a result, it was determined that small air pocket volumes located along the pipeline profile were recognized as the direct cause of the PCCP rupture. Further, a detail survey of the pipeline was performed using a combination of non-destructive technologies in order to determine if immediate intervention was required to replace PCC pipes. In addition, a hydraulic model was employed to analyze the behavior of air pockets located at high points of the pipeline.

show abstract

Section: Pipeline Accidentmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Failure Analysis of a Water Supply Pumping Pipeline System

Pozos‐Estrada

Sánchez-Huerta

Breña-Naranjo

et al. 2016

Water

View full text Add to dashboard Cite

show abstract

“…Further on, the critical velocity was thought to be a function of Froude number, Reynolds number, pipe angle and surface tension [9]. Pozos [5] proposed a formula for the critical velocity through experiments taking the bubble size into account. Liu [10] thought the critical velocity for a single bubble was regardless of the bubble size in large-diameter pipes and proposed a minimum Froude number instead of the critical Froude number in rough pipes.…”

Section: Introductionmentioning

confidence: 99%

“…In the inclined upward section of the water transmission pipeline, the air could be easily taken away due to buoyancy. In the horizontal pipe, Benjamin and Bakopoulos proposed a dimensionless number of 0.54 as the minimum flow rate for the bubbles starting to move; while Corcos suggested a dimensionless number of 0.484 for small diameter tubes [5]; and according to Escarameia's experiment [6], the critical velocity for bubble motion in the horizontal pipe was about 0.8 m/s, which was multiplied by a safety factor of 1.1. Therefore, the air could not be easily taken away when the water velocity is too small.…”

Section: Introductionmentioning

confidence: 99%

Study on Bubble Velocity under Bubble Flow Scenario in the Horizontal Water Transmission Pipeline

Zhu¹,

Wu²,

Yuan³

2015

Proceedings of the 2015 International Conference on Architectural, Civil and Hydraulics Engineering

View full text Add to dashboard Cite

Abstract. In order to put forward some feasible suggestions for the air emission in water transmission pipeline, this article mainly studies the bubble velocity under bubble flow scenario in the horizontal water transmission pipe. It was assumed that the bubble in the horizontal pipe could be regarded as a rigid body with a spherical shape, and the concept of sliding friction was introduced into the stress analysis to represent for the interaction between the bubble and the pipe wall. Taking all the forces on the bubble into consideration, a completely theoretical model was established to calculate the bubble velocity. During the experiments, the method of continuous photographing was employed to record the bubble size and velocity, and the experimental data was used to verify the accuracy of the model. It was found that the experimental data fitted well with the theoretical model after multiplying a correction factor. Ultimately, the corrected model was used to study the effects of pipe diameter, pipe variety, pipe pressure and temperature on the bubble size and bubble velocity, and it was proposed that more air release valves should be installed at the terminal part of the water transmission pipeline for air emission.

show abstract

“…This area has been studied in different contexts to date. Falvey (1980), Pozos et al (2010), Pothof and Clemens (2010) and others have studied the motion of air pockets and bubbles in pressurized mains with the objective of deriving an expression for the minimum water velocity that ensures air pocket removal from pipes (clearing velocity). The quasi-steady motion of discrete air pockets in pressurized pipe flows has been investigated in the context of multi-phase flow applications (DeHenau and Raithby, 1995).…”

Section: Introductionmentioning

confidence: 99%

Kinematics of Entrapped Air Pockets Within Stormwater Storage Tunnels

Chosie

Vasconcelos

2013

JWMM

View full text Add to dashboard Cite

During the rapid filling of stormwater storage tunnels, which is anticipated to occur during intense rain events, a number of different mechanisms may lead to the entrapment of air pockets, as described by Vasconcelos and Wright (2006). Entrapped air pockets have been linked to operational issues such as damaging surges, loss of storage capacity and severe geysering upon their release through water filled vertical shafts. However, the mechanisms behind the motion of these finite volume pockets following their entrapment still require further investigation.For discrete air pockets (as opposed to stratified air-water flow conditions) a balance between drag and buoyancy is expected to control the motion of large pockets in closed conduits. Previous related investigations approached the problem of pocket motion in the context of water mains, focusing on the determination of a minimum velocity to ensure air pocket removal. In the context of the rapid filling of stormwater tunnels, water flows cannot be pre-specified, and the pocket celerity thus becomes an important parameter, particularly in the context of numerical simulation for such flows.This chapter presents the preliminary results of an experimental investigation performed at Auburn University in which different air pocket volumes are released in pressurized closed pipe flow at selected slopes and flow rates. The kinematics of air pockets are studied for various flow conditions with the goal of obtaining a better understanding between observed pocket celerity and its relation to pocket volume, flow velocity and pipeline slope.

show abstract

Air entrapped in gravity pipeline systems

Cited by 47 publications

References 19 publications

Failure Analysis of a Water Supply Pumping Pipeline System

Failure Analysis of a Water Supply Pumping Pipeline System

Study on Bubble Velocity under Bubble Flow Scenario in the Horizontal Water Transmission Pipeline

Kinematics of Entrapped Air Pockets Within Stormwater Storage Tunnels

Contact Info

Product

Resources

About