Flame acceleration in pipes containing bends of different angles

Zhu, Chuanjie; Gao, Zi-shan; Lin, Baiquan; Tan, Zhong; Sun, Youhong; Ye, Qing; Hong, Youshi; Guo, Chunhui

doi:10.1016/j.jlp.2016.05.014

Cited by 14 publications

(6 citation statements)

References 23 publications

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“…Based on the above analysis, it can be seen that in contrast to straight pipelines or simple bifurcated pipelines 12 , 15 , 19 , 20 , the overpressure did not show a negative correlation with time during the attenuation process 21 , 22 . Rather, it experienced multiple up-down cycles.…”

Section: Results Analysis and Discussionmentioning

confidence: 91%

“…In straight pipelines, the overpressure attenuation coefficient is an important parameter to quantify the time-varying characteristics of the explosion overpressure 12 , 15 , 19 , 20 . Similarly, in curved or bifurcated pipelines, the overpressure attenuation characteristics can be optimally quantified using the overpressure attenuation coefficient 14 , 17 , 21 , 22 . After testing, the qualitative conclusions about the overpressure attenuation in some previous studies 12 , 22 , 28 , 30 also satisfied Eq.…”

Section: Results Analysis and Discussionmentioning

confidence: 99%

“…In summary, most of the previous studies on gas–coal dust explosion were carried out on simple bifurcated pipelines, long straight pipelines, or spherical explosion tanks 18 , 21 – 25 . These pipeline networks are not similar to an underground roadway.…”

Section: Introductionmentioning

confidence: 99%

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Propagation and attenuation characteristics of shock waves in a gas–coal dust explosion in a diagonal pipeline network

Jia

Xiuyuan

2022

Sci Rep

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In order to obtain the propagation and attenuation characteristics of a shock wave gas–coal dust explosion, a diagonal pipeline network was built to carry out a gas–coal dust explosion experiment. Methane with a volume fraction of 9.5% was mixed with 20 g of coal dust with a particle size of 50 μm. The shock wave attenuation characteristics in the diagonal pipeline network were characterized by the overpressure attenuation coefficient. The results showed that when the shock wave propagated in the diagonal pipeline network, it was offset and superposed multiple times. The overpressure attenuation in diagonal pipes was greater than that in the other pipeline branches. Secondary explosions occurred at all monitoring points. The propagation characteristics of shock waves is less affected by the pipeline network structure when it is close to the outlet of pipeline network. Nonlinear multivariate regression analysis was carried out to analyze the relationship between the overpressure attenuation coefficient and two adjacent monitoring points, the pressure before and after attenuation, and the pipeline angle. The functional relationship was in good agreement with the experiment data.

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Section: Results Analysis and Discussionmentioning

confidence: 91%

Section: Results Analysis and Discussionmentioning

confidence: 99%

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Propagation and attenuation characteristics of shock waves in a gas–coal dust explosion in a diagonal pipeline network

Jia

Xiuyuan

2022

Sci Rep

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“…Phylaktou et al also found that the flame propagation speed rose four-fold when bends were used [15]. However, the opposite effect was found by Zhu et al, who carried out experiments using different angles, and detected that the flame speed decreased significantly as it went around the bends [16]. However, it should be stressed that plenty of experimental research conducted on dust explosions are being carried out on a laboratory scale, where the operating conditions and variables are assumed to remain constant and are thus easier to control.…”

Section: Introductionmentioning

confidence: 96%

Influence of Bends in the Functionality of Passive Explosion Isolation Valves

Garrido-Ceca

Puig-Gamero²,

Ramírez-Gómez

2022

Applied Sciences

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Explosion isolation flap valves are one of the most used explosion protection systems in process industries; research is essential to improve them and to minimise both human and material losses when dust explosions take place. In this regard, there is little knowledge on the effect of bends in the functionality of these protective systems; hence, the main aim of this work is to bridge this gap. Large-scale dust explosions were performed, using three different types of dust: metal dust and two types of organic dust. In order to analyse the effect of bends in the functionality of these protective systems, results using a straight duct and one with bends were compared for each dust tested. In addition, the influence of the bend radius on aluminium dust explosions was also evaluated. The results indicated that the effect of bends depended on the explosive characteristics of the dust. However, for aluminium and maize starch dusts, bends led to higher pressures and flame velocities. Relevant information is provided to help decision-making when designing these valves. Moreover, such data can be used for consideration in the discussions held by the task force entrusted with developing the standard used to assess their functionality.

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“…In addition, the explosion characteristics of premixed gases are also different in explosion vessels with different geometric shapes. These geometric structures include bifurcations, − bends, , and connected containers. − Changes in the structure of the explosion vessel will reflect the pressure wave and disturb the air flow to form a turbulent flame, and the formation of a turbulent flame will increase flame propagation velocity and explosion overpressure.…”

Section: Introductionmentioning

confidence: 99%

Effect of Abrupt Changes in the Cross-Sectional Area of a Pipe on Flame Propagation Characteristics of CH₄/Air Mixtures

Wang

Fan

et al. 2021

ACS Omega

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To study the flame propagation characteristics of methane/air premixed gas in the pipeline with a sudden change of the pipe cross-sectional area, six kinds of customized pipes are used to study the methane/air premixed gas with a concentration of 9.5%. The results show that when the initial smooth flame front encounters an abrupt change in the cross-sectional area, the flame front becomes disordered and a turbulent flame is formed. A greater change in the cross-sectional area results in more severe flame turbulence. Compared with larger cross-section pipes set at the ignition end and downstream end, when the large cross-sectional area pipe is set in the middle of the pipe, the flame propagation process receives the secondary mutation induction effect of the abrupt cross section and the turbulence effect is stronger. The maximum propagation velocity and pressure are observed in configuration with the larger pipe in the middle of the pipe network. Moreover, when the cross-sectional area of this larger pipe increases, the flame is more substantially influenced by longitudinal expansion, the maximum propagation velocity and maximum overpressure increase accordingly, and the pressure oscillations are more obvious.

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Flame acceleration in pipes containing bends of different angles

Cited by 14 publications

References 23 publications

Propagation and attenuation characteristics of shock waves in a gas–coal dust explosion in a diagonal pipeline network

Propagation and attenuation characteristics of shock waves in a gas–coal dust explosion in a diagonal pipeline network

Influence of Bends in the Functionality of Passive Explosion Isolation Valves

Effect of Abrupt Changes in the Cross-Sectional Area of a Pipe on Flame Propagation Characteristics of CH₄/Air Mixtures

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Flame acceleration in pipes containing bends of different angles

Cited by 14 publications

References 23 publications

Propagation and attenuation characteristics of shock waves in a gas–coal dust explosion in a diagonal pipeline network

Propagation and attenuation characteristics of shock waves in a gas–coal dust explosion in a diagonal pipeline network

Influence of Bends in the Functionality of Passive Explosion Isolation Valves

Effect of Abrupt Changes in the Cross-Sectional Area of a Pipe on Flame Propagation Characteristics of CH4/Air Mixtures

Contact Info

Product

Resources

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Effect of Abrupt Changes in the Cross-Sectional Area of a Pipe on Flame Propagation Characteristics of CH₄/Air Mixtures