Self-Sustained Aeroacoustic Oscillations in Multiple Side Branch Pipe Systems

2009 ◽  
Author(s):  
Devis Tonon ◽  
Günes Nakiboglu ◽  
Johannes Willems ◽  
Avraham Hirschberg ◽  
Robert Leandro ◽  
...  
Keyword(s):  
Branch Pipe ◽  
Side Branch ◽  
Pipe Systems

Numerical Simulation of Acoustic Resonance in Closed Side Branch With Different Cross-Section Shapes

2018 ◽  
Author(s):  
Jiang LiuYi ◽  
Zhang Hong ◽  
Duan QingQuan
Keyword(s):  
Cross Section ◽  
Research Work ◽  
Branch Pipe ◽  
Acoustic Resonance ◽  
Side Branch ◽  
Pipeline System ◽  
Detached Eddy Simulation ◽  
Cross Section Shape ◽  
Section Shape ◽  
The Cross

There are many closed side branches in the gas conveying pipeline system. When the gas passes through the closed side branch, the shear layer will arouse the acoustic resonance in the closed side branch, which is harmful to the safe operation of the pipeline. The research work is insufficient about the influence of the cross-section shape of the closed side branch on acoustic resonance. Using the Detached-Eddy Simulation (DES) model, the acoustic resonance characteristics caused by the side branch pipe with different square cross-sections are simulated at the inlet boundary conditions of 25 m/s, 30 m/s and 35 m/s. The results show that in the center axis of the side branch, a 1/4 wavelength standing wave was formed, and the acoustic resonance occurs at a higher Strouhal number in circular branch. The cross-section shape of the side branch does not affect the acoustic resonance frequency, but it has a certain influence on the amplitude of pressure fluctuation and has a significant influence on the high-order frequency components.

What Is the Leak Rate for a Liquid Slug Flowing Past a Side Branch?

2020 ◽  
Author(s):  
C. Hartloper ◽  
E. Clavelle ◽  
K. Leong ◽  
M. Fitz ◽  
S. Epur
Keyword(s):  
Critical Velocity ◽  
Liquid Velocity ◽  
Branch Pipe ◽  
Branch Length ◽  
Side Branch ◽  
Leak Rate ◽  
Flow Loop ◽  
Chemical Cleaning ◽  
Set Up ◽  
Pipe Size

Abstract Chemical cleaning is used in gas pipelines to remove debris that was resistant to mechanical cleaning. The cleaner is a liquid mixture of a hydrocarbon-based solvent and a surfactant. It is transported down the pipeline either batched between two cleaning tools or pushed by a single tool. During a chemical cleaning run, liquid will leak into any side branch it passes. Consequently, gas quality problems may arise when the pipeline returns to regular operations as the leaked liquid hydrocarbons evaporate into the gas stream. Furthermore, operational problems such as flooded separators can occur if a large volume of liquid is lost. Currently, there is no understanding of what factors influence the liquid’s leak rate into side branches. This paper aspires to address this knowledge gap. A water flow loop was set up to investigate the effect on leak rate of mainline pipe size, side branch pipe size, side branch length, and mainline liquid velocity. The leak rate is found to increase with the side branch pipe size, while remaining unaffected by the mainline pipe size and side branch length. At mainline velocities below the critical velocity, gravitational effects such as the downstream back pressure significantly affect the leak rate. At mainline velocities above the critical velocity these effects disappear, and the leak rate decreases as the mainline liquid velocity increases.

Real-life Bifurcation – Challenges and Potential Complications

2011 ◽  
Vol 7 (4) ◽  
pp. 283
Author(s):  
Inga Narbute ◽  
Sanda Jegere ◽  
Indulis Kumsars ◽  
Dace Juhnevica ◽  
Agnese Knipse ◽  
...  
Keyword(s):  
Stent Thrombosis ◽  
Real Life ◽  
Coronary Intervention ◽  
Side Branch ◽  
The Body ◽  
Chronic Total Occlusions ◽  
Vein Grafts ◽  
Procedural Complications ◽  
Drug Eluting ◽  
Bifurcation Lesions

Together with calcified lesions, saphenous vein grafts, chronic total occlusions and unprotected left main lesions, bifurcation lesions are complex lesions that remain among the outstanding challenges of treatment with percutaneous coronary intervention. Bifurcation lesions are associated with increased rates of procedural complications, restenosis and adverse events than lesions in the body of the vessel. The introduction of drug-eluting stents for the treatment of bifurcation lesions has dramatically decreased restenosis rates, especially in patients suffering from diabetes. However, abrupt side branch closure, side branch ostial restenosis and stent thrombosis remain areas where further improvement is needed. Although a provisional T-stent strategy is most often used when side branch stenting is required, there are true bifurcation lesions where the selected use of more complex bifurcation approaches (such as the crush technique, T-stenting or the culotte technique) seem appropriate, particularly when the main branch and side branch are larger vessels with more diffuse side branch disease. The major challenge with any technique is to ensure that the side branch is protected and there is a satisfactory final result. Many technical questions rise in trying to ensure this outcome and lower the risk of intra- and post-procedural complications such as side branch closure and restenosis, stent thrombosis, dissection and fracture of a jailed wire: how can difficult side branch access be solved? How can unfavourable side branch anatomy be re-wired after main vessel stent placement? How can fracture of a jailed wire be avoided? Is side-strut dilation beneficial?

Dedicated Bifurcation Stents Strategy

2009 ◽  
Vol 4 (1) ◽  
pp. 70
Author(s):  
Chen Shao-Liang ◽  
Imad Sheiban ◽  
◽  
Keyword(s):  
Interventional Cardiology ◽  
Daily Practice ◽  
Side Branch ◽  
Control Groups ◽  
Coronary Bifurcation ◽  
Percutaneous Approach ◽  
Coronary Bifurcation Lesions ◽  
Drug Eluting ◽  
Bifurcation Lesions ◽  
Provisional Stenting

Coronary bifurcation lesions represent an area of ongoing challenges in interventional cardiology, mainly due to the higher rate of residual stenosis and restenosis at the side branch ostium. Multiple two-stent bifurcation strategies, including T-stenting, V-stenting, simultaneuos kissing stenting, culotte stenting and classic crush techniques, have no advantages over one-stent techniques. This led to provisional stenting being considered as a mainstream approach, based on the results of numerous randomised trials. Dedicated bifurcation stents have been designed specifically to treat coronary bifurcations with the aim of addressing some of the shortcomings of the conventional percutaneous approach and facilitating the provisional approach. The development of more drug-eluting platforms and larger studies with control groups demonstrating their clinical applicability, efficacy and safety are required before these stents are widely incorporated into daily practice.

Provisional and Complex Techniques for Bifurcation Treatment – Trading Apposition for Scaffolding?

2012 ◽  
Vol 7 (1) ◽  
pp. 44
Author(s):  
Nicolas Foin ◽  
Eduardo Alegria-Barrero ◽  
Ryo Torii ◽  
Pak H Chan ◽  
Ajay K Jain ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
New Technology ◽  
Coronary Intervention ◽  
Target Lesion ◽  
Side Branch ◽  
Simultaneous Increase ◽  
Stent Restenosis ◽  
Percutaneous Coronary ◽  
Stent Coverage ◽  
Bifurcation Lesions

Provisional T-stenting with stenting of the main branch and optional side branch (SB) stenting in the case of significant SB occlusion with thrombolysis in myocardial infarction (TIMI) flow <3 is the strategy chosen nowadays by most interventionalists for treating simple bifurcation lesions. Percutaneous coronary intervention (PCI) of complex true bifurcation lesions remains, however, the subject of debate: treatment of complex bifurcation lesions requires more time than treatment of simple bifurcations and can lead to significantly higher rates of restenosis, target lesion revascularisation and myocardial infarction. Current bifurcation techniques often fail to ensure continuous stent coverage of the SB ostium and of the two bifurcation branches without a simultaneous increase in the rate of malapposed struts. Stent struts left unapposed in the lumen disturb blood flow and are increasingly recognised as increasing the risk of stent thrombosis and focal in-stent restenosis, limiting the success of stent procedures in these lesions. New technology and dedicated designs may, in the near future, overcome such limitations of conventional two-stent bifurcation strategies.

Percutaneous Coronary Intervention for Complex Bifurcation Lesions

2010 ◽  
Vol 5 (1) ◽  
pp. 58
Author(s):  
Yves Louvard ◽  
Morice Marie-Claude ◽  
Thomas Hovasse ◽  
Thierry Lefèvre ◽  
◽  
...  
Keyword(s):  
Percutaneous Coronary Intervention ◽  
Coronary Intervention ◽  
Side Branch ◽  
Drug Eluting Stents ◽  
Open Angle ◽  
Balloon Inflation ◽  
Percutaneous Coronary ◽  
Drug Eluting ◽  
Bifurcation Lesions ◽  
Stent Diameter

Coronary bifurcations are prone to the development of atherosclerosis. They pose technical difficulties for angioplasty treatment and are a predictor of stent thrombosis and restenosis. Treatment of coronary bifurcations is still subject to debate, especially when the side branch (SB) is large, not easily accessible and narrowed by a long lesion. There is currently no indexed treatment for this type of lesion (Medina classification), as the strategy of provisional SB stenting with drug-eluting stents (DES) has proved to be equally efficient as the dualstent technique. Complex techniques are associated with poor outcome in certain lesion types, such as T-stenting when the angle between the two distal branches is small or the crush and culotte technique in the presence of an open angle. Provisional SB stenting may be used when primary dual stenting is required, with a low risk of failure provided that the following guidelines are implemented: stenting of the main branch through the protected SB with a stent diameter adapted to the distal main branch, immediate optimisation of the proximal stent segment (Finet’s law), guidewire exchange, kissing balloon inflation with non-compliant balloons selected according to the diameter of the distal branches and T-stenting of the SB before final kissing inflation.

Type II Endoleak:Transperitoneal Sacotomy and Ligation of Side Branch Endoleaks Responsible for Aneurysm Sac Expansion

2002 ◽  
Vol 9 (4) ◽  
pp. 539-542 ◽  
Author(s):  
Robert J. Hinchliffe ◽  
Ravinder Singh-Ranger ◽  
Simon C. Whitaker ◽  
Brian R. Hopkinson
Keyword(s):  
Side Branch ◽  
Type Ii
Sign in / Sign up

Export Citation Format

Share Document