Explosion Accidents Research Articles

Research on emergency evacuation behavior rules of pedestrians under fire and explosion accidents in chemical parks considering social relationships

Chemical parks present a high risk of sudden accidents such as fires and explosions, given the significant number of hazardous sources present. This is why emergency evacuation after accidents is so essential. The behavior of crowds during evacuation is complex, and social relationships among pedestrians can have differentiated effects on the evacuation process. However, most of the current crowd evacuation research has focused on life scenarios and natural disaster contexts. Less attention has been paid to the emergency evacuation of crowds affected by social relations in the context of chemical accident disasters. A comprehensive evacuation model that considers the dynamic evolution of crowd transfer both within and outside the factory area is proposed in this paper. Using the Anylogic software based on the social force model, this study constructs emergency evacuation scenarios for crowd in the context of fire and explosion accidents, and toxic gas leakage incidents. Specifically, this study analyzes the impact of three factors, namely inter-personal distance, group size, and proportion of different group sizes in the total population, on the evacuation efficiency. It has been found that when large groups of pedestrians are split into smaller ones for evacuation, the evacuation efficiency can be effectively improved. The study includes calculations of the lethal range of a toxic gas and simulated the process of relocating large crowds of people to nearby shelters. In addition, a strategy for deploying pedestrian groups based on social relationships was developed for the context of mass evacuation. These measures have the potential to optimize the evacuation efficiency of pedestrian groups in chemical parks, including expanding and modifying shelters, diverting dense crowds from residential plots, using interpersonal spacing of 0.1 m, and splitting large groups of pedestrians into smaller ones. The research results can provide a reference for decision making for large-scale group evacuation in chemical parks, and improve the emergency evacuation capability and local risk response capability in chemical parks.

Fuzzy multi-criteria decision-making framework for controlling methane explosions in coal mines

The structure of underground coal mines is vulnerable to many mishaps because of the challenging conditions of production and the unique features of the earth. These incidents could cause significant financial and production losses for the mines in addition to worker injury, disability, or death. In coal mines, methane explosions are a frequent threat. Establishing a safe work environment requires managing these problems with an accident control method. The current study used the fuzzy TOPSIS and fuzzy AHP techniques for this aim. The framework was used to tackle the four-alternative problem of underground coal mine explosion control method selection. To identify potential risks of a methane explosion, a data gathering survey was conducted as part of the suggested hybrid methodology. The fuzzy AHP was used to compute the fuzzy weights of the hazards. “Improper ventilation system” is ranked highest out of the 34 sub-risk factors. The fuzzy TOPSIS was then utilized to rank the explosion control methods using the weights. To assess the viability of the study’s conclusions, a sensitivity analysis was carried out. The findings indicate that “improving safety technology” and “financial investments” are the best ways to reduce such events. The results additionally indicate that the fuzzy TOPSIS approach in combination with the fuzzy AHP provides a helpful framework for dynamically assessing mine methane explosion accidents.

Cause analysis of secondary explosion accident in Hushan Gold Mine, Shandong Province, China based on HFACS-CM model

Explosion accidents often occur during mining, especially sudden secondary explosions, which pose a serious threat to the life and property safety of employees. Based on the development process and consequences of typical secondary explosion accidents in Hushan Gold Mine, Qixia City, Shandong Province, China, this paper uses accident analysis model and cone measurement calculation method to determine the direct cause of secondary explosion accidents. The main conclusions are as follows: The HFACS-CM model is used to analyze the causes of secondary explosion from five aspects: external environment, organizational influence, unsafe leadership, the prerequisite conditions of unsafe behavior and unsafe behavior. It is found that the CO ignition explosion in the mining process is the direct cause of secondary explosion. Then, combined with the experimental data of the cone measuring instrument, the field CO amount was calculated, and the MCO ≥ 101.4 m3 was obtained, indicating that the CO production did reach the condition of explosion range, and the analysis results of the model were verified. Through HFACS-CM model analysis and calculation verification, the key causes of secondary explosion accidents in such mines are found and lessons are learned, which provides an effective reference for the effective prevention of deflagration accidents in the field of mine safety.

Numerical Evaluation of Harmful Consequences after Accidental Explosion at a Hydrogen Filling Station

Abstract This study aims to present computational technology that can be used to evaluate numerically the harmful environmental consequences caused by an accidental hydrogen release from failed high-pressure dispensing cylinders and its explosion at a vehicle hydrogen filling station. A coupled problem of a hydrogen explosion products expansion in the atmospheric ground layer and a harmful explosion pressure wave shock impact on service personnel and infrastructure buildings at an accident site is solved by means of computer experiment simulation series. A spatial time-dependent model of compressible hydrogen-air mixture flow is used to obtain pressure history in calculation area in order to assess maximum overpressure in control points of human possible locations and on building surfaces exposed to hydrogen blast wave impact. A deterministic impact consequences model is based on comparing maximum overpressure values extracted from the mathematical model with threshold ranges corresponding to certain degrees of human damage and infrastructure destruction. The presented computer technology allows safety experts to identify potentially dangerous zones by means of mathematical modelling and recommend effective protection measures to mitigate negative consequences of explosions.

Accidental Explosions, Beirut ANFO Blast, Ghana Truck Explosion, Global Terrorism Index 2021-22, and Blast Mitigation: A Review

Explosions are continually occurring without ceasing in many parts of the world endangering human lives and seriously affecting the health of infrastructures and facilities. Industry accidental mishaps that occurred recently, like those in Ghana (2022; 17 deaths), Russia (2021; 18 deaths), Beirut (2020; 220 deaths; $8bn economic loss), and Tientsin (2015, 173 deaths; $6.86bn economic loss), indicate the severity of the industrial devastation one could gauge that explosions may cause. Very recently, another industrial blast occurred at a rocket and explosive factory in the capital city of Turkey leading to the collapse of a nearby building and causing 5 deaths and serious injuries to over 50 civilians, is an eye-opener. This article offers a condensed examination of subjects related to explosions, including accidental detonations, the Beirut ANFO explosion, and the Ghana truck explosion. The report findings from the global terrorism index 2021-22 are analyzed and discussed. Additionally, strategies for both active and passive measures to mitigate the impact of explosions on infrastructure and facilities are emphasized. To ensure safety and durability against damage, the structure needs to possess resilience in the face of explosions. Therefore, it is crucial to analyze how the structure responds to extreme loading in order to enhance the design philosophy. Currently, there is still a lack of understanding regarding the mechanism of blast and how it affects masonry structures. Consequently, further research is required to delve deeper into this subject.

CFD Simulation and ANN Prediction of Hydrogen Leakage and Diffusion Behavior in a Hydrogen Refuelling Station

Hydrogen refueling station (HRS) is an essential part of the infrastructure for promoting the hydrogen economy. Since hydrogen is a flammable and explosive gas, hydrogen released from high‐pressure hydrogen storage equipment in HRS will likely cause combustion or explosion accidents. Studying high‐pressure hydrogen leakage in HRS is a prerequisite for promoting hydrogen fuel cell vehicles and HRS. A computational fluid dynamics (CFD) model of an HRS in a demonstrated project in Ningbo, China, was established on the ANSYS FLUENT software platform. The CFD model for hydrogen leakage simulation was validated by comparing the simulation results with experimental data in the literature. The effects of the direction and mass flow rate of the hydrogen leakage jet, as well as the direction and speed of ambient wind, on hydrogen diffusion behavior were investigated. The spreading distances of the flammable hydrogen cloud were predicted using an artificial neural network for horizontal leakage. The results show that the jet direction strongly affected the flammable cloud flow. The greater the mass flow rate of the leak, the greater the hydrogen dispersion distance and the volume of the flammable hydrogen cloud. At a hydrogen leakage mass flow rate of 4.5589 kg/s, the volume of the hydrogen flammable cloud reached 6,140.46 m3 at 30 s of leakage. The ambient wind speed has complicated effects on spreading the flammable cloud. The wind makes the flammable cloud move in certain directions, and the higher wind speed accelerates the diffusion of the flammable gas in the air. The results of the study can be used as a reference for the study of high‐pressure hydrogen leakage in HRS and will play an important role in the safe demonstration of the studied project.

Environmental impacts caused by fire and explosion accidents in maritime activities: A review

Environmental impacts caused by fire and explosion accidents in maritime activities: A review

Numerical study on detonation initiation by multiple hot spots

Detonation initiation is important not only for the development of advanced detonation engines and but also for the control of accidental explosion. There are mainly two types of detonation initiation, i.e., direct initiation and indirect initiation. This work focuses on direct detonation initiation which has a short initiation distance but requires large amount of energy deposition. Specially, we investigate the reduction in the critical initiation energy through replacing the single hot spot by multiple hot spots. The transient detonation initiation process in a stoichiometric H2/O2/Ar mixture is examined through two-dimensional simulations considering detailed chemistry. It is found that under the same initiation energy, detonation initiation fails for a single large hot spot while successful detonation initiation can be achieved by employing six small hot spots. The collisions among adjacent transverse detonation waves induce new local explosions, which play a pivotal role in detonation initiation. To further assess the impact of wave collision, we change the hot spot energy used in the multiple hot spot configuration. For relatively low initiation energy, the blast wave quickly decays and decouples with the reaction zone. Consequently, the collision among transverse shock waves cannot induce new local explosion and detonation initiation fails. Increasing the initiation energy can enhance the blast wave and is favorable to the formation of local explosion, facilitating the rapid detonation initiation. Furthermore, the influence of hot spot number on detonation initiation is assessed. Interestingly the hot spot number is found to have non-monotonic effect on detonation initiation. Splitting a single hot spot into multiple hot spots enhances detonation initiation since the wave collision helps to induce local explosion. However, as the hot spot number increases, the energy of each hot spot is decreased and becomes excessively dispersed, which results in relatively weak blast wave and thereby weak wave interaction. Consequently, local explosion cannot be triggered and detonation initiation fails for relatively large hot spot numbers. This study provides insights on promoting detonation initiation through multiple hot spots.

Защита человека от ударных волн средствами инженерно-технической укреплённости

Purpose. Protective screens (barriers) are used in areas with large crowds of people to reduce the likelihood of human injury from explosive devices used in terrorist acts. To assess the effectiveness of protective screens, it is necessary to determine the following initial data in advance: the weight of the explosive device in TNT equivalent; the area being protected, and the acceptable probability of human injury within it. The article presents a general methodology for determining the effectiveness of protective barriers against terrorist-directed explosive devices. An example is given of using the developed methodology to determine the most optimal solution for protective barriers for a specific object. Methods. Various numerical simulation methods are used to solve gas dynamics problems. When modeling explosions accompanied by shock impacts, the Godunov’s scheme – solving the breakdown of an arbitrary discontinuity problem – is used. The problem of the breakdown of an arbitrary discontinuity in numerical schemes is reduced to a system of nonlinear equations related to the pressure and velocity of the medium at the discontinuity point, which determine the mass and momentum fluxes exchanged between adjacent computational cells. Findings. The author's experimental research methodology allows obtaining all the necessary information about the parameters of explosive loads formed during internal accidental explosions. Research application field. The research results can be used in the design of anti-terrorist protective structures. Conclusions. Blast loads are presented for the placement of anti-terrorist protective structures. Reduction in blast loads is shown for three different placement options of protective structures. The conditional probability of human injury by an air shock wave is determined. Based on the found parameters, the effectiveness of anti-terrorist protective structures is assessed for three different placement options.

Analysis of damage to ship personnel in different seated postures by near-field underwater explosions

With the frequent occurrence of ship explosion accidents at sea, the safety of ships and crews has attracted much attention. At present, the research on crew injury is relatively weak. Consequently, the current study constructs a numerical model of the ship structure-crew-blast flow field to investigate the discrepancies in injury response of crew members across different sitting postures. LS-DYNA software is used for simulation and direct analysis to evaluate the damage of crew members in different positions under 100 kg TNT equivalent and 2 m blast distance conditions, and the relationship between different explosive equivalents and crew damage is analyzed. The results demonstrate that for crew members situated in working compartment, the injuries incurred across different sitting postures also differed. The lower leg and foot sections were at greater injury risks, while the head area was associated with minimal damage risks. Altering upper body postures of the crew human body had only a very small impact on lower extremity injuries. Moreover, positive correlations were exhibited between explosive equivalents and crew injury values. The research findings may offer references for injury analysis and protective device design of naval personnel.

Experimental simulation study on gas flow field in combined goaf during the transition period of coal pillar-free working face relocation

Regarding the gas disaster caused by the complex ventilation system and the changeable flow field in the combined goaf during the transition period of the coal pillar-free working face, the self-designed physical simulation test bench for the combined goaf of coal pillar-free mining was used to compare and analyze the distribution law of wind pressure, gas, and oxygen concentration field in the combined goaf during the moving period of the working face and the normal mining period. The results show that during the relocation period, the gas concentration in the stope will always be slightly higher than that in the normal mining period, and the existing air leakage channel will lead to complex air flow in the combined goaf, which is easy to cause gas explosion accidents. The formation conditions, judgment principles, and judgment methods of the dangerous area of gas explosion coupling disaster in goaf are analyzed. By changing the air distribution ratio of the main and auxiliary air intake roadways, it is concluded that the explosion area will form an “L”-shaped explosion zone in the goaf, and the area of gas explosion disaster area during the relocation period will be larger than that the normal mining period. According to the size of the gas explosion area, the optimal air distribution ratio of the main and auxiliary air intake roadway during the transition period of the working face relocation and the normal mining period is 2:1. Under this air distribution ratio, the gas explosion area is the smallest, which is 132 284 and 113 534 mm2, respectively. The research results are of great significance to reveal the mechanism of gas disaster induced by goaf during the transition period of coal pillar-free relocation.

Study on the characteristics parameters of magnesium dust explosion suppression by various inert gases

Alongside the extensive use of magnesium, dust explosion accidents have become increasingly frequent. Conducting research on suppressing magnesium dust explosions is of great significance for the healthy development of the magnesium industry. In this paper, the effects of four inert gases (CO2, N2, Ar, and He) on the explosion characteristics parameters of magnesium dust clouds with different concentrations were investigated using a closed explosion device. It was observed that at low volume fractions of inert gases in the explosion system, there were no significant differences in their effects on the explosion characteristics parameters and the combustion time of magnesium particles. In situations where there was a high level of oxygen, N2 was more effective than Ar in suppressing explosions. However, when the concentration of magnesium dust cloud was higher and the oxygen content was lower within the hybrids, N2 reacted with magnesium dust that was unable to react with oxygen. As a result, the explosion suppression effect gradually shifted from N2 being better than Ar to Ar being better than N2. Moreover, the differences in the effects of four inert gases on particle combustion time became increasingly prominent. However, in all operating conditions, CO2 demonstrated the most effective suppression of magnesium dust explosions, while He exhibited the least effective suppression effect. Furthermore, by employing a chemical reaction kinetics calculation model, it has been discovered that the content of inert gases significantly affected the combustion time and reaction mode of particle combustion, thereby causing variations in the propagation behavior of magnesium dust cloud flames.

Modeling and performance analysis of emergency response process for hydrogen leakage and explosion accidents

To address concerns associated with the initial response process following hydrogen refueling station leakage and explosion accidents, this research introduces the utilization of stochastic colored Petri nets for dynamic modeling of the emergency response procedure. Through the construction of a process model for responding to hydrogen leakage and explosion accidents at refueling stations, the model's effectiveness is assessed using an Isomorphic Markov chain (MC) analysis approach, followed by simulation and analysis of the emergency response procedure. Furthermore, the performance of the emergency process in managing hydrogen leakage and explosion accidents at refueling stations is evaluated, considering place occupancy probabilities and transition utilization probabilities. By optimizing the timing of transitions, critical stages in the process for handling hydrogen leakage and explosion accidents at hydrogen refueling stations are identified, and recommendations for process enhancement are proposed. The findings reveal that continuous hydrogen leakage conditions and the phase involving the summoning of rescue personnel are prone to information congestion. The timely arrival of the on-site manager and the prompt reporting of incident details emerge as pivotal actions within the emergency response process for hydrogen refueling station leakage and combustion incidents. These actions wield substantial influence over the efficacy of emergency response and mitigation, underscoring their significance as primary areas for improvement.

Understanding the Factors and Consequences of Gas Deflagration Accident in Metro Shield Tunnel: Site Investigation and Numerical Analysis

This study aims to investigate the factors and consequences of gas deflagration accidents in metro shield tunnels based on on-site investigation and numerical analysis. We built a numerical model and detection process for an underground shield tunnel subjected to an internal explosion from an actual accident. The tunnel geometry under consideration is the same as that used for the metro line. Concerning the limitations of research on the failure and recovery mechanism of shield segmental linings under the action of internal explosion load, an explosion accident of a shield segmental lining under construction caused by the shield tunneling machine destroying natural gas pipelines was discussed, in which the structure failure characteristics during the explosion and the structure repair method after the explosion were investigated. An interval repair scheme was proposed, which provides experience for the treatment of similar engineering accidents. To investigate the gas explosion within the tunnel during the accident, the finite element software Ansys LS-DYNA with the arbitrary Lagrangian–Eulerian (ALE) technique was employed to simulate the explosion scenario. Dynamic analyses were carried out to reproduce the blast scenario. The stress distribution within the segmental lining as well as the lining’s deformation were calculated. The potential applications of the treatment and planning of comparable engineering mishaps were discussed in the study.

Research on quantitative risk assessment method of dust explosion based on Bayesian network

In order to effectively prevent the occurrence of dust explosion accidents in industrial enterprises and reducing the risk of dust explosion accidents, the article builds dust explosion risk assessment index system for industrial enterprises, taking Fault Tree Analysis (FTA) and Event Tree Analysis (ETA) as theoretical basis and establishes dust explosion risk Bow-Tie Analysis (BT) diagram model. Mapping BT model into Bayesian Networks (BN) reveals the coupling mechanism of dust explosion risk nodes and constructs a generic dust explosion risk assessment BN model, which provides a quantitative assessment of the probability of occurrence of dust explosion accidents. The causative mechanism of dust explosion accidents is investigated by learning risk inference from this model. It is also demonstrated that appropriate safety barrier measures can effectively reduce the probability of accidents, thereby changing the accident level and improving the safety and reliability of the system. Finally, the validity and applicability of the model is verified through empirical analyses. The research results contribute to the scientific prediction of the probability of dust explosion risk and reasoning learning, which provides a scientific basis for enterprises to formulate effective dust explosion safety measures as well as to realize the hierarchical control of dust explosion risk.

Gas explosion impact behavior and disaster analysis based on structural failure: Numerical modeling

For gas leakage explosion accidents that occur in high blockage environments, the failure of building structures often leads to the evolution of explosion waves becoming unpredictable, resulting in the amplification of accident consequences. In this paper, a severe gas leakage and explosion accident in Beijing is analyzed using computational fluid dynamics (CFD) method, and the disasters of the accident are evaluated based on the evolution of physical quantities. The laws of propagation and impact damage of explosion waves based on structural failure are also summarized. Based on the numerical analysis results, the explosion of 4.0–4.1 m3 combustible gas is sufficient to destroy a large number of walls with a maximum indoor overpressure of 1.130 bar and create a high-pressure injury area of 10 m and a high-temperature injury area of 14 m outdoors. The impact behaviours of explosion waves are closely related to the building structures and obstacle characteristics. Structures whose spatial direction is the same as the propagation direction of the initial wave suffer less damage, and similar obstacle characteristics on both sides of structures reduce damage. The disorder of gas explosion intensity leads to the unpredictable failure direction and process of building structures, and the collapse direction of component may be opposite to the path of initial explosion wave; Outdoors, the gas flow rate of several hundred meters and the peak dynamic pressure of 0.5 bar caused all the glass of two buildings to break. Therefore, a reasonable pressure relief area and sufficient safety distance become the key measures to prevent and mitigate the disaster of civil explosion accidents. The research results can provide scientific basis for the investigation and loss prevention of explosion accidents, as well as safety assessments in the process industries.

Oxygen vacancy–enriched Y2O3 nanoparticles having reactive facets for selective sensing of methyl ethyl ketone peroxide explosive

Methyl ethyl ketone peroxide (MEKP) is a highly-reactive and exothermically unstable compound that has caused many explosion accidents. Therefore, a simple, rapid and sensitive method for online monitoring of MEKP is urgently required to address such problems. Herein, yttrium oxide (Y2O3) nanoparticles with different levels of oxygen vacancies (OV) and exposed reactive facets were synthesised at different calcination temperatures. Gas-sensing studies revealed that a cataluminescence (CTL) sensor based on Y2O3 nanoparticles annealed at 600 °C achieved the highest response to MEKP with a limit of detection of 1 ppb at a working temperature of 80 °C. Density functional theory calculations indicated the {222} and {440} facets in Y2O3 as the most reactive sites towards MEKP. Moreover, the introduction of OV into the exposed reactive facets can considerably enhance the adsorption of O2 and MEKP on Y2O3 nanoparticles. Further sensing mechanism studies unveiled the singlet and triplet excited states of acetaldehyde produced by the catalytic oxidation of MEKP as the possible luminophores for CTL emission. This study not only offers a promising method for online monitoring of MEKP but also offers deep insights into the improved sensing mechanism caused by OV and exposed reactive facets, thus providing guidance for designing high-performance CTL sensors.

Study on flexible/rigid protection mechanism of hydrogen/methane premixed gas explosion in urban underground space

Explosion accidents are one of the factors that impede urban underground space development and utilization, and it is imperative to study safety precautions in case of an explosion in an urban underground space. Given this problem, a polyurethane sponge and carbon fiber board with Blocking Rates (BR) of 0.2, 0.4 and 0.6 were used to explore the combustion and explosion characteristics of hydrogen/methane premixed gas in a confined space in the presence of a flexible and rigid obstacle. The results indicated that both the flame and pressure exhibit Helmholtz oscillation characteristics in case of a rigid obstacle. When the BR of both flexible and rigid obstacle were 0.4, the explosion intensity index was the highest. It first increased and then declined with the increase of flexible obstacle BR. In the presence of a flexible obstacle, the Helmholtz oscillation phenomenon was completely suppressed, and explosion intensity indices were minimized, as the flexible obstacle BR increased, it first increased and then declined. Under the rigid obstacle preset conditions, the explosion hazard significantly increased compared to the flexible constructions. The research results provide a theoretical basis for protective facilities to suppress combustion and explosion phenomena in underground spaces.

Highly selective and ultra-sensitive gas sensor based on Fe2O3/Ti3C2Tx MXene heterostructure for ppb-level n-butanol detection

The sensitive and rapid detection of toxic gases, particularly at concentrations as low as parts per billion (ppb), is crucial in preventing explosion and gas leakage accidents. Herein, we have developed a ppb-level n-butanol sensor by constructing a heterojunction structure through in situ growth of n-type oxide semiconductor Fe2O3 nanoparticles on two-dimensional layered carbide materials Ti3C2Tx MXene. The obtained results from that the Fe2O3/MXene-1% sensors display ultra-low detection limit, exhibiting a 1.31 response towards 70 ppb n-butanol. In addition, the Fe2O3/MXene-1% sensors show a remarkable response of 83.7 towards 100 ppm n-butanol at 150 °C, which represents a 22-fold improvement when comparison with the pure Fe2O3 sensors. The sensors also exhibit brilliant selectivity, reproducibility and excellent long-term stability. The remarkable enhancement in gas sensitive performance depends on Schottky heterojunctions formed between metal oxides and Ti3C2Tx MXene and the synergistic effect. The incorporation of MXene decreases materials’ resistance and enhances the carrier transfer rate. The design of this study provides a novel approach for achieving ppb-level n-butanol detection.

Head injuries evaluation during a pipeline explosion

In recent years, Mexico has suffereda series of explosive accidents linked to oil drilling and fuel pipeline operations. These explosions are often triggered by the rapid vapor expansion due to abrupt pressure changes, known as Boiling Liquid Expanding Vapor Explosions (BLEVEs). Tragically, in 2019, a devastating explosion occurred in Tlahuelilpan, claiming the lives of at least 100 people and injuring many others. This research aims to investigate brain injuries resulting from such explosions. Despite the potential for severe injuries, there is a significant lack of comprehensive injury data, with most research focusing on military contexts. In this study, we employed the Baker method in three configurations, utilizing a finite element model, Hybrid III 50Th Percentile Male Standing, in LS-Dyna®. Head Injury Criteria (HIC) is a measure for acceleration behavior in head. Our findings indicate that this value for acceleration, and BLAST propagation radio decrease with greater analysis distance. Brain injuries include edemas, contusions, lacerations, and skull compression, predominantly affecting individuals within a 6-meter radius of the detonation point.