Fire Accidents Research Articles

Study on cooling efficiency and mechanism of lithium-ion battery thermal runaway inhibition by additives enhanced water mist based on boiling heat transfer theory

In recent years, fire and explosion accidents caused by thermal runaway (TR) of lithium-ion batteries (LIB) have occurred frequently, which has become one of the main obstacles restricting its development. Therefore, it is urgent to develop fire extinguishing agents with high cooling efficiency to inhibit the growth of TR. The water mist is an effective choice, but it shows poor performance with the rise in cell temperature under TR. In this study, two additives, KCl and the nonionic fluorocarbon surfactant FC-4430, were added to the water mist to improve the cooling efficiency. In addition, the inhibition effect exerted by the modified water mist during the whole process of lithium-ion battery TR was experimentally investigated. Furthermore, the influence of water mist with additives on the Leidenfrost effect in the high temperature range was deduced, and the reinforcement cooling mechanism was analyzed by heat transfer theory. The results show that KCl and FC-4430 can increase the initial cooling rate in the high temperature range by 48.6%–120%. The reinforcement mechanism is attributed to changing the medium's physical parameters with additives. On the one hand, the Leidenfrost point of the droplets on the cell surface is increased, which in turn extends the temperature range of the nucleate boiling stage, and on the other hand, the heat flux density and heat transfer of the water mist in the film boiling state are increased.

The strategy of using heme proteins and synthetic porphyrins as injectable antidotes for fire gas poisoning

Abstract During fire accidents, 2 highly toxic components of fire smoke, carbon monoxide (CO) and hydrogen cyanide (HCN), are produced simultaneously, and more than 50% of fire-related deaths can be attributed to the inhalation of these toxic gases. Despite the different CO and HCN detoxification mechanisms, oxygen (O2) ventilation is currently the primary clinical treatment, and no alternative methods are available at present. In this review, the toxicological mechanisms of CO and HCN are investigated with an emphasis on the toxic effects of their combination. On the basis of these toxic mechanisms, the advantages and disadvantages of the current clinical detoxification methods are analyzed and discussed. We also summarize the latest advancements in the development of CO- and HCN-scavenging antidotes, highlighting the strategy of using synthetic iron porphyrins that have been synthesized mainly in our laboratory as water-soluble synthetic hemoglobin biomimetics.

A Design and Safety Analysis of the “Electricity-Hydrogen-Ammonia” Energy Storage System: A Case Study of Haiyang Nuclear Power Plant

With the development of modernization, traditional fossil energy reserves are decreasing, and the power industry, as one of the main energy consumption forces, has begun to pay attention to increasing the proportion of clean energy generation. With the deepening of electrification, the peak-valley difference of residential electricity consumption increases, but photovoltaic and wind power generation have fluctuations and are manifested as reverse peak regulation. Thermal power plants as the main force of peak regulation gradually reduce the market share, making nuclear power plants bear the heavy responsibility of participating in peak regulation. The traditional method of adjusting operating power by inserting and removing control rods has great safety risks and wastes resources. Therefore, this paper proposes a new energy storage system that can keep the nuclear power plant running at full power and produce hydrogen to synthesize ammonia from excess power. A comprehensive evaluation model of energy storage based on z-score data standardization and objective parameter assignment AHP (analytic hierarchy process) analysis method was established to evaluate energy storage systems according to a multi-index system. With an AP1000 daily load tracking curve as the input model, the simulation model built by Aspen Plus V14 was used to calculate the operating conditions of the system. In order to provide a construction basis for practical engineering use, Haiyang Nuclear Power Plant in Shandong Province is taken as an example. The system layout scheme is proposed according to the local environmental conditions. The accident tree analysis method is combined with ALOHA 5.4.1.2 (Areal Locations of Hazardous Atmospheres) hazardous chemical analysis software and MARPLOT 5.1.1 geographic information technology. A qualitative and quantitative assessment of risk factors and the consequences of leakage, fire, and explosion accidents caused by hydrogen and ammonia storage processes is carried out to provide guidance for accident prevention and emergency rescue. The design of an “Electric-Hydrogen-Ammonia” energy storage system proposed in this paper provides a new idea for zero-carbon energy storage for the peak shaving of nuclear power plants and has a certain role in promoting the development of clean energy.

Safety Requirement of Electric Facilities in BESS Fire Accidents Viewpoint

Safety Requirement of Electric Facilities in BESS Fire Accidents Viewpoint

Experimental Study on Evaporation and Ignition Behavior of RP-3 Fuel with Different Leakage Volumes on Hot Surface

ABSTRACT Fire accidents caused by fuel leakage to hot surfaces are of significant concern in the aerospace domain due to their potential for severe consequences. This paper investigates the evaporation and ignition characteristics of fuel leakage to a hot surface through a series of experiments with different volumes of RP-3 droplets. The evolution patterns of evaporation lifetime, ignition position, and ignition delay time are examined. The results show that within the surface temperature range of 500–700°C, the fuel droplets of all volumes almost immediately reach the film boiling state upon contact with the hot surface. The droplets move erratically across the surface, changing shape from irregular to elliptical and finally to spherical. The evaporation lifetime decreases with increasing hot surface temperature. The occurrence of ignition is stochastic, and the ignition probability rises with the hot surface temperature, while the minimum ignition temperature decreases with the increase of fuel volume. The movement of the fuel droplets in the film boiling state leads to the irregularity of the ignition position. Additionally, the ignition delay time decreases with an increase in the temperature of the hot surface. The relationship between ignition delay time and surface temperature in the film boiling state is discussed in the context of the vapor plume model and boiling heat transfer analysis.

Numerical Study on the Effects of Horizontal Barriers on Fire Behavior in Logistics Facility Racks

In this study, a numerical analysis was conducted to derive the optimal installation conditions for flame-spread barriers within racks, to reduce the damage caused by recurrent fire accidents in logistics facilities. The effectiveness of the fire extinguishing system according to domestic regulations was reviewed to ensure the feasibility of installation of the horizontal barrier. This review revealed that sprinkler systems were ineffective in delaying or preventing the initial spread of fire under certain fire conditions, confirming the need for horizontal barriers. Furthermore, although the installation of horizontal barriers was effective in delaying the initial fire spread, it led to an increase in fire size by blocking the extinguishing water and altering the fire spread path. It was confirmed that deriving the optimal installation conditions for barriers requires the consideration of the interactions between the in-rack sprinkler heads and the surrounding fire extinguishing systems.

Numerical Simulation of an Isolated N-Heptane Pool Fire

Refineries are industrial complexes of great economic importance which are located close to major cities. A pool fire accident that can occur from an oil leak combined with wind can result in disastrous consequences for such an industry. This study investigates the characteristics of an isolated n-heptane square pool fire of 36 m2 under the influence of a cross wind. The pool fire characteristics are numerically studied using open-source Computational Fluid Dynamics (CFD) software, such as FireFoam (v4.1) and Fire Dynamic Simulator (FDS) (version 6.9.0). The turbulent flow field and the fire characteristics were simulated with the LES Method. The crucial parameters of the pool fire, such as (a) the temperature and velocity fields, (b) the flame length and height, (c) the surface emissive power, and (d) the flame tilt angles, were computed. Comparisons against experimental data for both small and large-area pool fires from the literature were made successfully. The flame tilt angle is shown to correlate very well with the reciprocal of the Richardson number, which was approximated within a multiplication constant to the Froude number. Thus, both the reciprocal Richardson number and Froude number can be used for correlating the flame tilt angle. It is shown that both of these numbers are used to correlate the tilt angle of experimental pool fires with effective diameters from a fraction of a meter to approximately 16 m, and wind speeds up to 7 m/s. The goodness of a linear fit based on the sum of the residual squares is 0.91.

Research on fire accident prediction and risk assessment algorithm based on data mining and machine learning

Forest fire is a kind of natural disaster that is destructive, easy to spread, and difficult to extinguish. It greatly harms the balance of ecosystem and human life and property. The prediction and risk assessment of forest fire accidents can find forest fires as early as possible and then take corresponding remedial measures; the loss of forest fires will be minimized. This paper first collected the relevant data information in the Lesser Hinggan Mountain region, established the fire driving factor database, and then analyzed the impact and distribution characteristics of forest fire driving factors such as temperature and rainfall. Finally, a fire accident prediction model was built based on a deep neural network, and the model’s performance was compared with the SVM and RF models. The analysis results show that this paper’s fire accident prediction model is more accurate.

Investigation of the Minimum Ignition Energy Required for Combustion of Coal Dust Blended with Fugitive Methane

Ventilation Air Methane (VAM) significantly contributes to global warming. Capturing and mitigating these emissions can help combat climate change. One effective method is the thermal decomposition of methane, but it requires careful control to prevent explosions from the high temperatures involved. This research investigates the influence of methane concentration and coal dust particle properties on the minimum ignition energy (MIE) required for fugitive methane thermal decomposition and flame propagation properties. This knowledge is crucial for the mining industry to effectively prevent and mitigate accidental fires and explosions in VAM abatement plants. Coal dust samples from three different sources were selected for this study. Experiments were conducted using a modified Hartmann glass tube and a Thermal Gravimetric Analyser (TGA). The chemical properties of coal dust were determined through ultimate and proximate analysis. The particle size distribution was determined using a Mastersizer 3000 apparatus (manufactured by Malvern Panalytical, Malvern, UK). The results showed that the MIE is significantly affected by coal dust particle size, with smaller particles (<74 µm) requiring less energy to ignite compared to coarser particles. Additionally, blending methane with coal dust further reduces the MIE. Introducing methane concentrations of 1% and 2.5% into the combustion space reduced the MIE by 25% and 74%, respectively, for the <74 µm coal dust size fraction. It was observed that coal dust concentration can either raise or lower the MIE. Larger coal dust concentrations, acting as a heat sink, reduce the likelihood of ignition and increase the MIE. This effect was noted at a methane concentration of 2.5% and coal dust levels above 3000 g/m3. In contrast, small amounts of coal dust had little impact on MIE variation. Moreover, the presence of methane during combustion increased the upward flame travel distance and propagation velocity. The flame’s vertical travel distance increased from 124 mm to 300 mm for a coal dust concentration of 300 g·m−3 blended with 1% and 2.5% methane, respectively.

Development and Characterization of Thermal Protection Gels for Steel Pipelines Transporting Combustible Materials

Due to low costs, pipelines are commonly used for transporting hazardous substances such as combustible liquids and gasses. Currently, chemical industrial parks and gas production stations have dense pipeline networks. In the case of a pipeline leakage and subsequent fire accident, the adjacent pipelines could be directly impinged by the flame or engulfed in hot smoke, with the potential to result in a chain of accidents and catastrophic consequences. It is thus of practical importance to develop an efficient thermal protection material for pipelines. In this study, a new type of bio-based gel material was prepared for pipeline thermal protection, using guar gum (GG) as the gelling agent, sodium tetraborate (B) as the crosslinking agent and magnesium chloride (MgCl2) as the fire retardant. Firstly, orthogonal experiments were conducted to examine the gelling time of the gel and determine the optimal formulations that meet the protection requirements. Subsequently, water retention, thermal stability and the microstructure of these formulations were analyzed. Finally, the thermal protection performance of the gel formulations was evaluated under the direct impingement of flames or high-temperature smoke. The results indicated that the best performance was achieved by the formulation with GG, B and MgCl2 mass fractions of 2.5, 0.6 and 0.5 wt%, respectively. This formulation also exhibited the best water retention capacity and thermal stability. In the pipeline thermal protection experiments, this formulation achieved effective protection times of 216 s (for a 90 mm diameter) and 312 s (for a 120 mm diameter) for the lower part of the pipeline under direct flame impingement. Under high-temperature smoke impingement, this formulation also showed excellent performance. These research and findings can provide an important foundation for the further development of thermal protection materials for pipelines under fire conditions.

Predicting smoke temperature distribution beneath ceiling for a large subway station fire

Fire accident seriously threatens the stable operation and personnel security in the subway station, and clarifying the smoke temperature distribution is conducive to arranging reasonably fire alarm. In this study, model experiments and numerical simulations are conducted to investigate the ceiling temperature profiles, mainly altering the heat release rate (HRR) and fire locations in a large subway station. The repeatability of the experimental data is confirmed, and the numerical model is validated by the measurement data. During a fire happening in a large-wide space, the smoke movement beneath the ceiling can be divided into radial and one-dimensional flow, whose prediction models are proposed under fire source located at the center. On this basis, it can be found that the radial temperature profile is independent of fire source location. While, the one-dimensional temperature distribution model is modified by introducing the effects of transvers and longitudinal fire locations respectively. This work could provide data support and theoretical reference for clarifying the smoke movement for large subway station fire.

Utilizing cerium as a surrogate for actinide aerosols: Real-time characterization and formation mechanisms in nuclear fire scenarios

Characterizing radioactive aerosol particles released from actinide metals on fires represents a pivotal process in nuclear emergency response. However, the precise characterization of these particles and the deep understanding of their formation mechanism remain a daunting challenge due to the lack of in-situ measurement techniques. We presented the first real-time investigation of respirable particles with the size ranging from 2 nm to 10 μm, emitted from the combustion of cerium metal (CM) as surrogate for actinide counterparts. The evolution of such particles was revealed by the methodology combining scanning mobility particle sizer and optical particle sizer, showing the consistent generation of multimodal ultrafine particles with diameters of 2–100 nm during the combustion reaction. Numerous polydisperse 0.2–0.5 μm accumulated particles and a few 2–10 μm coarse particles were also produced via droplet dispersion and explosion during molten CM self-enhanced combustion. These particles were predominantly composed of CeO2 and exhibited lognormal distributions. The spherical, aggregated, chain-like and fractured particles implied the evolution of particles including nucleation, coagulation, agglomeration and oxide layer cracking. Comparative analyses of particle size distributions reveal that bulk CM combustion predominantly generated ultrafine particles in the absence of CM droplet dispersion. Our finding will guide a critical evaluation of respirable actinide aerosols in the case of fire accidents involving actinide metals.

Research on scenario extrapolation and emergency decision-making for fire and explosion accidents at university laboratories based on BN-CBR

To solve the problems of suddenness, uncertainty and untimely emergency decision-making related to fire and explosion accidents in university laboratories, a combined method of BN and CBR is introduced to analyze laboratory accidents. By summarizing the characteristics of 72 accident cases worldwide, four scenario elements with key roles are extracted by combining the public safety triangle theoretical model; a BN is established from the macro perspective, which is based on the construction of dynamic scenarios; the evolution path is analyzed via BN theory; and the probability of occurrence of accidents is quantified from the microscopic perspective, with a focus on the analysis of the accidental evolution process. A case similarity calculation is carried out via CBR, and the construction of a BN-CBR-assisted decision-making model is completed, verified and corrected in an case study. The results show that the BN-CBR model can quickly determine the accident evolution path and the most similar historical cases, and its quantitative probability calculation enables one to comprehensively grasp the real-time state of the whole accident and the emergency response in a timely manner, which provides a new way to approach emergency decision-making of accidents.

Study on pedestrian evacuation simulation model considering group behavior

As a crowded place on the university campus, the cafeteria inevitably has many safety hazards, such as fire accidents caused by open flames and large appliances, stampede accidents caused by overcrowding during peak dining hours, etc. Therefore, studying pedestrian evacuation in university campus cafeterias is particularly necessary. Pedestrians on campus mostly travel in groups. Previous studies mainly used continuous models to discuss pedestrian group evacuation behavior. In this study, based on the cellular automaton pedestrian evacuation simulation model, the floor field calculation method was improved. A cellular automaton pedestrian evacuation simulation model considering group behavior was established and applied to the evacuation scenario of students in a university campus cafeteria. The study found that under the different group configurations, the pedestrian ratios, and the pedestrian densities, the pedestrian evacuation efficiency had significant differences. The results showed that when the different group configurations existed in the scenario, the higher the proportion of the pedestrians with three-person front-to-back group configurations, the higher the evacuation efficiency. When only one type of the group configuration existed in the scenario, at low pedestrian density, the evacuation efficiency of the individual pedestrian groups was higher compared to the other six group configurations. While at high pedestrian density, the evacuation efficiency of the three-person front-to-back group configurations was higher. These findings provided important references for pedestrian evacuation in university campus cafeterias and provided insights for the simulation research of group pedestrian evacuation models, contributing to enhancing campus safety management and ensuring the safety of teachers, students, and staff.

A novel conjugated microporous polymer nano hollow sphere containing N, P and Si flame retardant elements with both thermal insulation and flame retardant properties

It is particularly important to develop new materials with both thermal insulation and flame retardant properties for addressing the severe issues caused by fire accidents. Herein, a kind of conjugated microporous polymer nanospheres with hollow structure (HCMPNS) was synthesized by Sonogashira-Hagihara cross-coupling reaction using SiO2 nanospheres as hard template and 1,3,5-triacetylenebenzene, as alkynyl monomer. Then, HCMPNS was chemically graft-modified with azidotrimethylsilane (TMSA) by "click" chemistry (HCMPNS-FRSi), and the HCMPNS-FRSi obtained from the reaction was introduced into flammable epoxy resin (EP) to obtain EP based composites, i.e. EP-Ⅰ and EP-Ⅱ. The thermal conductivities were found to be 0.0341 W m−1 K−1 and 0.0268 W m−1 K−1 for EP-Ⅰ and EP-Ⅱ, respectively, showing excellent thermal insulation performance. The total heat release (THR), the total smoke production (TSP) and the peak CO2 produced (CO2P) of EP-Ⅰ were reduced by 18.0 %, 8.0 %, 14.3 % compared with pure EP as measured by cone calorimetry (CC), respectively, indicating a certain extent flame retardant effect. In order to further improve its flame retardant properties, phosphoric acid containing the flame retardant phosphorus element was added to HCMPNS-FRSi (HCMPNS-FRSi-P), followed by the introduction of the resulting HCMPNS-FRSi-P into EP matrix to form EP based composites with Si and P dual incorporation (EP-III and EP-IV), with the thermal conductivities of 0.0470 W m−1 K−1 and 0.0855 W m−1 K−1, respectively. Through the cone calorimetry (CC) of EP-III, EP-IV, total heat release (THR) were reduced by 17.0 %, 23.8 %, total smoke production (TSP) were reduced by 6.2 %, 7.2 %, respectively. The peak heat release rate (HRR) and the peak CO2 produced (CO2P) of EP-Ⅳ were reduced by 16 % and 25 %, respectively, compared with pure EP. It has good thermal insulation and flame retardant effect. Therefore, HCMPNS-FRSi-P, as a new type of flame retardant material, has great potential in the fields of electronics, construction, transportation and so on.

Enhanced air filtration and ammonia sensing with cellulose nanofibers-based triboelectric nanogenerators under harsh environments

Fire accidents often occur in environments characterized by severe air pollution, toxic gas emissions, and microbial growth, creating significant challenges for developing multifunctional portable healthcare devices. These devices must achieve high filtration efficiency, minimal pressure drop, and the capability to provide early warnings of toxic gas leaks. Triboelectric nanogenerators present a sustainable solution as self-powered energy converters for advanced healthcare applications. In this study, we grafted Ti3C2Tx/MoS2 nanohybrid materials, which form Schottky heterojunctions, onto cellulose diacetate using tetraethyl orthosilicate, followed by electrospinning to produce nanofibrous films. When paired with a negatively charged material, the resulting device achieved an optimal balance with a low-pressure drop (52 Pa) and high filtration efficiency (98.72 % for PM0.3). It also demonstrated exceptional stability under high-temperature and high-humidity conditions. Notably, the device maintained rapid sterilization within 15 min and consistent filtration performance even after multiple washes. Furthermore, the device exhibited precise detection of trace amounts of NH3 (0.1 ppm) and demonstrated a rapid response, achieving an 86 % response rate within 2 s for 100 ppm NH3, providing an early warning 28 s faster than commercial NH₃ monitors. This study introduces a novel approach to the development of multifunctional, self-powered, wearable medical devices that offer high-efficiency air filtration and sterilization, breath monitoring, and rapid toxic gas leakage detection in harsh environments.

Effects of fuel distribution on thermal environment and fire hazard

AbstractFire accidents in buildings are occurring and claiming thousands of lives each year. Due to various architectural designs, fire hazards would be unique to each building layout. This paper discusses how fire hazard varies with the arrangement of the fuel inside buildings. To comprehensively present the effect of fuel distribution on fire behaviour, results from large‐scale experiments, bench‐scale experiments, empirical correlations, and numerical studies are provided. In large‐scale fire tests, two different cases of wood cribs were tested to demonstrate the effects of porosity on heat generation and fire spread behaviour. Due to the limitations of experimental conditions, the variation in heat release rate attributable to differences in fuel porosity and surface area has been also qualitatively investigated using a cone calorimeter test. To bring the gap between experimental observations and real‐word scenarios, a numerical study is also performed. This study further explores the effects of fuel distribution (considering porosity and surface area of fuel throughout the compartment) and ventilation on fire spread beyond the fire compartment. The computational fluid dynamics (CFD) simulations show how the distribution of fuel in different ways can lead fire to spread beyond its origin, as observed in many fire accidents. The paper suggests that designers should consider such critical fire scenarios in performance‐based design.

A new method for thermal runaway warning of electric vehicle charging

Abstract With the large-scale development of electric vehicle (EV) in China, the frequent occurrence of EV fire accidents has attracted the attention of insiders to the fault monitoring and early warning during the charging process of EV. According to data from the National Emergency Management Ministry, there were over 3,000 EV fire accidents nationwide in 2023, underscoring the urgency for enhanced fault monitoring and early warning measures. In response to these issues, this article proposes an EV thermal runaway early warning method based on Temporal Convolutional Network (TCN) and Gated Recurrent Unit (GRU) by combining the two technologies. The method aims to improve EV safety by monitoring battery status for early thermal runaway warning. First, the historical normal charging data of the battery are preprocessed and feature extracted using the TCN, and then features fed into GRU for time-series modeling and forecasting. This combined model not only demonstrates high prediction accuracy and stability but also swiftly responds to abnormal conditions during charging, effectively preventing thermal runaway accidents and ensuring charging safety. Furthermore, this model possesses excellent generalization capabilities and can adapt to different types and specifications of EV battery systems.

Fire Risk Model for Fires in Ro-Ro Ship Ro-Ro Spaces

In recent years, fire accidents on Ro-Ro ships have led to numerous fatalities and significant economic losses. The response of the crew and the ship's protection systems are crucial in managing these incidents and mitigating their consequences. To assess fire safety improvements, this study has focused on developing and quantifying a risk model that captures the dynamics of a fire starting in a Ro-Ro space. Various risk modelling techniques were reviewed to construct the model, which was then quantified using historical data, simulations, and expert judgments. A Delphi-based, fully digital approach to expert elicitation was introduced, utilizing Microsoft Teams and Microsoft Excel-based questionnaires. This method ensured full anonymity for the experts, reducing the risk of group bias and eliminating the need for travel. To enhance understanding and verify the results, uncertainty and sensitivity analyses were performed. They revealed that the potential loss of life deviated, with 90% confidence, from the calculated mean value by less than 26%. Overall, the questionnaire-based method proved effective for expert elicitation and for quantifying nodes in the risk model, demonstrating its utility in the risk assessment process.

Investigation into the mechanism of ignition of magnesium alloy plates by high-temperature molten droplet

The ignition and spread of magnesium alloy fires are mainly attributed to the ignition of high-temperature molten metal droplets, but the underlying ignition mechanism remains unclear. This study addresses this knowledge gap by employing metallic aluminum and copper particles heated to temperatures over 1200 °C. Systematically, these heated particles were released at a fixed rate onto a magnesium alloy plate located inside a controlled heating furnace that maintained a constant temperature of 500 °C. Experimental results show that whether there are irregular pores and cracks in the resulting molten product can be used as a criterion for judging whether the magnesium alloy sample ignites. Furthermore, it is worth noting that molten copper droplets of the same size exhibit a higher heat-carrying capacity than their aluminum counterparts when both are heated to the same temperature. In addition, this study expanded the research scope through numerical simulation and analysis, using the PATO (Porous-Material Analysis Toolbox) solver to clarify the transient heat conduction process between the high-temperature droplet and the magnesium alloy plate. Simulations show that heat transfer upon droplet impact is primarily longitudinal, directed toward the base of the material. This results in a significantly higher temperature in the center of the affected magnesium alloy plate than at its periphery. In summary, this study helps to improve the understanding of the dangers of high-temperature molten droplets, and it is of great significance to investigate fire accidents caused by high-temperature molten droplets.