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Article
Publication date: 28 April 2014

Qi Zhang, Lei Pang and Dachao Lin

The high-velocity wind caused by a methane-air explosion is one of the important hazardous effects in explosion events of coal mines, and, however, until now it has not…

Abstract

Purpose

The high-velocity wind caused by a methane-air explosion is one of the important hazardous effects in explosion events of coal mines, and, however, until now it has not been received much attention from scientific works. The paper aims to discuss this issue.

Design/methodology/approach

In consideration of the difficulties in observing particle velocities of high-velocity flows, this work presented a study to reveal the regularity during a methane-air explosion happening in the tunnel of coal mine through the numerical analysis approach.

Findings

The strong wind caused by a methane-air explosion is a significant hazard and can cause damage in the accidents of methane-air explosion in underground coal mines, especially at structural opening, according to this work. Obtained results show that maximum particle velocity of the high-velocity wind occurs in the outside region of the premixed area, with a peak value of 400∼500 m/s, and the peak velocity of the high-velocity wind decreases exponentially with distance beyond the premixed area.

Originality/value

The objective of this work was to examine the effect of wind caused by a methane-air explosion in a tunnel. Other information, such as shock wave and flame and temperature distribution, has been reported in the previous literatures. However, in the accidents of methane-air explosion in underground coal mines, some phenomena (structural opening is destroyed badly) can not be understood by using shock wave and flame and temperature distribution caused by the explosion. The strong wind caused by a methane-air explosion is another significant hazard and can cause damage in the methane-air explosion accidents in underground coal mines, especially at structural opening, according to this work.

Details

Engineering Computations, vol. 31 no. 3
Type: Research Article
ISSN: 0264-4401

Keywords

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Article
Publication date: 13 May 2021

Lei Pang, Qianran Hu and Kai Yang

The purpose of this paper is to ascertain the harm to personnel and equipment caused by an external explosion during natural gas explosion venting. The external explosion

Abstract

Purpose

The purpose of this paper is to ascertain the harm to personnel and equipment caused by an external explosion during natural gas explosion venting. The external explosion characteristics induced by the indoor natural gas explosion are the focal points of the investigation.

Design/methodology/approach

Computational fluid dynamics technology was used to investigate the large-scale explosion venting process of natural gas in a 6 × 3 × 2.5 m room, and the characteristics of external explosion under different scaled vent size (Kv = Av/V2/3, 0.05, 0.08, 0.13, 0.18) were numerically analyzed.

Findings

When Kv = 0.08, the length and duration of the explosion fireball are 13.39 and 450 ms, respectively, which significantly expands the degree and range of high-temperature hazards. The suitable flow-field structure causes the external explosion overpressure to be more than twice that indoors, i.e. the natural gas explosion venting overpressure may be considerably more hazardous in an outdoor environment than inside a room. A specific range for the Kv can promote the superposition of outdoor rupture waves and explosion shock waves, thereby creating a new overpressure hazard.

Originality/value

Little attention has been devoted to investigating systematically the external explosion hazards. Based on the numerical simulation and the analysis, the external explosion characteristics induced by the indoor large-scale gas explosion were obtained. The research results are theoretically significant for mitigating the effects of external gas explosions on personnel and equipment.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0961-5539

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Article
Publication date: 28 October 2014

Qi Zhang and Qiuju Ma

Whether a fire can be initiated in an explosion accident depends on the explosion and deflagration process. In the methane-air explosion in a tunnel, the flame accelerates…

Abstract

Purpose

Whether a fire can be initiated in an explosion accident depends on the explosion and deflagration process. In the methane-air explosion in a tunnel, the flame accelerates from the ignition point. However, where it begins to decelerate is not clear. The purpose of this paper is to examine the explosion overpressure, flow and flame propagation beyond the premixed area of methane-air in a tunnel.

Design/methodology/approach

The numerical simulation was used to study the explosion processes of methane-air mixtures in a tunnel. Based on the numerical simulation and its analysis, the explosion overpressure, flow and flame propagation rules beyond the premixed area were demonstrated for a methane-air explosion.

Findings

The peak overpressure of methane-air mixture explosion was observed to reach its maximum beyond the original premixed area of methane-air. The hazardous effects beyond the premixed area may be stronger than those within the premixed area for a methane-air explosion in a tunnel. Under the conditions of this study, the ratio between the length of combustion area (40 m) and that of original premixed area (28 m) reaches 1.43.

Originality/value

Little attention has been devoted to investigating the explosion overpressure, flow and flam propagations beyond the original premixed area of methane-air in a tunnel. Based on the numerical simulation and the analysis, the propagation rule of overpressure wave and flow inside and outside the space occupied by methane/air mixture at the volume fraction of 9.5 percent in a tunnel were obtained in this work.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 24 no. 8
Type: Research Article
ISSN: 0961-5539

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Article
Publication date: 2 November 2015

Lei Pang, Lei Liu, Yong Kang and Pengfei Lv

Gas explosion is one of the most major types of accident in mining projects, and the flame front with high temperature is major hazardous factor induced by this kind of…

Abstract

Purpose

Gas explosion is one of the most major types of accident in mining projects, and the flame front with high temperature is major hazardous factor induced by this kind of accident. Support engineering provides an available way to solve problems related to ground movements, but very likely has a great influence on the gas explosion accident process, especially the flame propagation, and then aggravates mining risk. However, until now it has not been received much attention from scientific works. The paper aims to discuss these issues.

Design/methodology/approach

A commercial CFD software package AutoReaGas suitable for gas explosion is used to carry out the numerical investigation of gas explosion process in a straight coal tunnel with typical support engineering, especially the unsteady explosion field and the flame propagation process in it.

Findings

Support engineering composed by multiple bars take positive influence on flame acceleration: the flame speed is much faster than that under no support bars, and the smaller support spacing induces greater flame speed near the ignition. The support bars also exert negative influence on flame acceleration: the larger support spacing induces greater flame speed in most region of the tunnel. Furthermore, a traditional viewpoint that denser obstacles induce greater explosion effects is one-sided according to this study.

Originality/value

At present, no one concerns the aggravating influence of support engineering on accident risk in practical mining projects because of small geometric dimension. This work examines the effect of steel support system on evolution processes of gas explosion accidents, especially the flame propagation. The conclusions provide quantitative scientific basis for this kind of the accidents in risk evolution and accident investigation of mining engineering.

Details

Engineering Computations, vol. 32 no. 8
Type: Research Article
ISSN: 0264-4401

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Article
Publication date: 18 January 2016

Gu Gong and Hua Zhu

The purpose of this study satisfied the need for rapid, sensitive and highly portable identification of an explosion gas. In our study, a battery-operated, low-cost and…

Abstract

Purpose

The purpose of this study satisfied the need for rapid, sensitive and highly portable identification of an explosion gas. In our study, a battery-operated, low-cost and portable gas detection system consisting of a cataluminescence-based sensor array was developed for the detection and identification of explosion gas. This device shows how the discriminatory capacity of sensor arrays utilizing pattern recognition operate in environments.

Design/methodology/approach

A total of 25 sensor units, including common metal oxides and decorated materials, have been carefully selected as sensing elements of 5 × 5 sensor array. Dynamic and static analysis methods were utilized to characterize the performance of the explosion gas detection system to five kinds of explosion gases. The device collects images of chemical sensors before and after exposing to the target gas and then processes those images to extract the unique characteristic for each gas. Hierarchical cluster analysis (HCA) and principal component analysis (PCA) were used to analyze the image patterns.

Findings

Our study demonstrated that the portable gas detection device shows promising perspective for the recognition and discrimination of explosion gas. It can be used for the olfactory system of robot made by integrating the electronic nose and computer together.

Originality/value

The device collects images of chemical sensors before and after exposing to the target gas and then processes those images to extract the unique characteristic for each gas. HCA and (PCA were used to analyze the image patterns. Our study demonstrated that the portable gas detection device shows promising perspective for the recognition and discrimination of explosion gas. It can be used for olfactory system of robot made by integrating the electronic nose and computer together.

Details

Sensor Review, vol. 36 no. 1
Type: Research Article
ISSN: 0260-2288

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Article
Publication date: 26 August 2014

Qiuju Ma, Qi Zhang and Jiachen Chen

The purpose of this paper is to study propagation characteristics of methane explosion in the pipe network and analyze the propagation laws of methane explosion wave along…

Abstract

Purpose

The purpose of this paper is to study propagation characteristics of methane explosion in the pipe network and analyze the propagation laws of methane explosion wave along the elbow pipe and pipe network.

Design/methodology/approach

Numerical simulation using software package AutoReaGas, a finite-volume computational code for fluid dynamics suitable for gas explosion and blast problems, is adopted to simulate the propagation characteristics of methane explosion and the property of flow field in complex structures.

Findings

Due to reflection effects of corners of elbow pipe, the peak overpressures at corner locations in the elbow pipe go about two times higher than that in the straight pipe. In the parallel pipe network, the peak overpressure increases significantly at the intersection point, while the flame speed decreases at the junction. All these indicate that pipe corners and bifurcations could substantially enhance explosion partly which can bring more severe damage at the corner area. The explosion violence is strengthened after flames and blast waves are superimposed, such that equipments and people in these areas need special strengthening protection.

Originality/value

The numerical results presented in this paper may provide some useful guidance for the design of the underground laneway structures and to take protective measures at corners and bifurcations in coal mines.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 24 no. 7
Type: Research Article
ISSN: 0961-5539

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Article
Publication date: 7 June 2013

Qi Zhang and Lei Pang

Explosions are the main type of accident causing casualties in underground coal mines. Little attention has been devoted to investigating the flame propagations for…

Abstract

Purpose

Explosions are the main type of accident causing casualties in underground coal mines. Little attention has been devoted to investigating the flame propagations for methane‐air explosion in a tunnel with full scale. This paper seeks to address this topic.

Design/methodology/approach

Based on the numerical simulation and the analysis, the propagation rule of flame and temperature waves inside and outside the space occupied by methane/air mixture at the various concentrations in a tunnel were obtained in this work.

Findings

The original interface of methane‐air mixture and air moves forward in the explosion and the original mixture area extends. For the methane‐air mixture with rich fuel concentration, the flame speed increases with distance within a range beyond the original position of the interface between the mixture and air. The flame speed reaches maximum value outside the original area of methane‐air mixture with rich fuel concentration.

Originality/value

Based on the numerical simulation and the analysis, the propagation rule of flame and temperature wave inside and outside the space occupied by methane/air mixture at the various concentrations in a tunnel were obtained.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 23 no. 5
Type: Research Article
ISSN: 0961-5539

Keywords

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Article
Publication date: 1 October 2020

Osama Bedair

This paper reviews engineering work developed for blast analysis and design of industrial/residential and ammunition storage facilities. The review also covers work done…

Abstract

Purpose

This paper reviews engineering work developed for blast analysis and design of industrial/residential and ammunition storage facilities. The review also covers work done for progressive collapse analysis and blast deflectors.

Design/methodology/approach

The first part of the paper describes characteristics of various types of explosions. Empirical and numerical models that were developed to estimate structural capacity are reviewed. The structural idealization, theoretical basis, and merits of various methods are also described. The influence of various parameters affecting the structural performance is discussed.

Findings

The material of the paper captures recent engineering developments that can be used by practitioners for blast analysis and design for industrial and residential buildings. Little emphasis was given in the published literature to develop simplified analytical models that can be used in practice to compute the dynamic response of buildings subject to accidental explosions. Furthermore, analytical expressions are required to compute the reduction in the stiffness due to impact loading.

Originality/value

Current building codes address conventional live, dead, wind and earthquake loads. Very few guidelines are available in practice for design of buildings subject to blast loading. The objective of this paper is to review and piece together recent engineering work developed for blast analysis and design of industrial/residential buildings and ammunition facilities. The paper provides useful resource material for the engineers in practice using recent techniques to design these structures. The review covers past three decades that can be used as a baseline for future developments.

Details

Multidiscipline Modeling in Materials and Structures, vol. 17 no. 2
Type: Research Article
ISSN: 1573-6105

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Article
Publication date: 1 April 1959

A.C. SMITH

FIRES and oil explosions are known to have occurred in compressed air systems since the earliest days of the air compressor. Attempts to make systematic surveys of the…

Abstract

FIRES and oil explosions are known to have occurred in compressed air systems since the earliest days of the air compressor. Attempts to make systematic surveys of the extent of the hazard have never given very comprehensive results, but there is no doubt that it deserves serious attention.

Details

Industrial Lubrication and Tribology, vol. 11 no. 4
Type: Research Article
ISSN: 0036-8792

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Article
Publication date: 1 October 1998

Joseph Scanlon

The literature available on how communities deal with mass death, in particular body handling procedures, is sparse. Describes the actions of the various people involved…

Abstract

The literature available on how communities deal with mass death, in particular body handling procedures, is sparse. Describes the actions of the various people involved in the immediate aftermath of the Halifax (Nova Scotia) 1917 explosion. Also, but in less detail, examples the Rapid City flood, the Gander air crash, the Zeebrugge ferry disaster, the Tangsham earthquake, the Texas City explosion and the Kobe earthquake. Highlights the problems of handling bodies after a mass fatality incident: respect accorded to the dead individual; whether skilled individuals are there to take on the tasks, the tagging and identification procedures required and the setting up of temporary morgue facilities.

Details

Disaster Prevention and Management: An International Journal, vol. 7 no. 4
Type: Research Article
ISSN: 0965-3562

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