Fire Safety Journal最新文献_第2页

A computational study of the deposition of firebrands between two side-by-side blocks 两块并排木块之间火带沉积的计算研究

IF 3.4 3区工程技术

Fire Safety Journal Pub Date : 2024-10-04 DOI: 10.1016/j.firesaf.2024.104270

{"title":"A computational study of the deposition of firebrands between two side-by-side blocks","authors":"","doi":"10.1016/j.firesaf.2024.104270","DOIUrl":"10.1016/j.firesaf.2024.104270","url":null,"abstract":"<div><div>The deposition of firebrands between two blocks, representing neighboring simplified structures, was investigated by large-eddy simulation and Lagrangian tracking of firebrands. Fire Dynamics Simulator was modified and implemented for simulations. The computational configuration resembled the previous wind-tunnel measurement setup including two blocks and the firebrand generator apparatus, aka NIST Dragon (Suzuki and Manzello 2021). Different wind speeds and frictional coefficients between the sliding firebrands and the ground were considered. Simulations revealed several flow effects influencing the motion of firebrands on the ground, such as re-circulation flow in the wake of the dragon, a crossflow upwind of the blocks, and twin re-circulation regions on leeward and windward sides of the blocks. At lower wind speeds, firebrands were accumulated somewhere between the dragon and the blocks, consistent with observations in the previous measurements. At higher wind speeds, the firebrands tended to accumulate momentarily before the crossflow region and then accelerate through the gap between the blocks. Some accumulated in the leeward corner of the blocks. Firebrands displayed much more dispersion in the streamwise direction compared to the spanwise direction because the normal component of the Reynolds stress was greater in the streamwise direction.</div></div>","PeriodicalId":50445,"journal":{"name":"Fire Safety Journal","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142442887","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Computational analysis of flame spreads over alcohol fuel at sub-flash temperatures using multi-step chemistry 利用多步化学法计算分析亚闪光温度下酒精燃料的火焰蔓延情况

IF 3.4 3区工程技术

Fire Safety Journal Pub Date : 2024-10-04 DOI: 10.1016/j.firesaf.2024.104271

引用次数: 0

Formation mechanism and microstructural analysis of blistering marks on overcurrent copper wires 过电流铜线上起泡痕迹的形成机理和微观结构分析

IF 3.4 3区工程技术

Fire Safety Journal Pub Date : 2024-09-22 DOI: 10.1016/j.firesaf.2024.104268

引用次数: 0

Partial gravity flammability of cast PMMA rods in concurrent axial stagnation flow 铸造 PMMA 棒材在并行轴向滞流中的部分重力可燃性

IF 3.4 3区工程技术

Fire Safety Journal Pub Date : 2024-09-19 DOI: 10.1016/j.firesaf.2024.104267

{"title":"Partial gravity flammability of cast PMMA rods in concurrent axial stagnation flow","authors":"","doi":"10.1016/j.firesaf.2024.104267","DOIUrl":"10.1016/j.firesaf.2024.104267","url":null,"abstract":"<div><div>Testing was performed in a partial gravity centrifuge drop vehicle in the Zero Gravity Research Facility with cast PMMA rods in concurrent axial buoyant stagnation flow to determine flammability limits as a function of partial gravity level. The partial gravity levels studied varied from 0.04 g to a simulated 1g for ambient oxygen concentrations from 13.2 % to 15.2 % O<sub>2</sub> by volume at an average 57.6 kPa (8.4 PSIA) ambient pressure, which is very close to the anticipated Lunar habitat pressure. The PMMA flammability boundary as a function of oxygen concentration and gravity level has been determined at five gravity levels. Coriolis effects appear to be minimal in the stagnation region where the flame is stabilized while the tips of the flame do show some bending at the higher gravity levels. Lunar gravity levels are near the minimum in the oxygen - gravity level flammability boundary. This suggests that fire is a significant safety risk for future exploration missions to the Moon since materials are screened in normal gravity to evaluate their safe use in space. If normal gravity screening is not conservative, a material derating method will need to be applied to ensure the material is not flammable on the Moon. Since the blowoff boundary appears to be linear with forced flow velocity, it may be possible to conduct elevated forced flow blowoff testing that could then be extrapolated down to effective Lunar gravity levels to provide an oxygen delta between 1g and Lunar flammability limits to derate the material.</div></div>","PeriodicalId":50445,"journal":{"name":"Fire Safety Journal","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142323244","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A Bayesian analysis of domestic fire response and fire injury 对家庭火灾响应和火灾伤害的贝叶斯分析

IF 3.4 3区工程技术

Fire Safety Journal Pub Date : 2024-09-14 DOI: 10.1016/j.firesaf.2024.104266

引用次数: 0

Numerical model of aerial drop characteristic of mass firefighting units for aerial firefighting 用于空中灭火的大规模灭火装置空投特性的数值模型

IF 3.4 3区工程技术

Fire Safety Journal Pub Date : 2024-09-13 DOI: 10.1016/j.firesaf.2024.104263

{"title":"Numerical model of aerial drop characteristic of mass firefighting units for aerial firefighting","authors":"","doi":"10.1016/j.firesaf.2024.104263","DOIUrl":"10.1016/j.firesaf.2024.104263","url":null,"abstract":"<div><p>The aerial drop characteristic of mass firefighting units has a significant influence on the effectiveness of aerial firefighting. In order to accurately describe the aerial drop characteristic of mass firefighting units, a numerical model covering the fundamental stages of the whole operation process was developed in the present study. In the model, mass firefighting units' filling and discharging processes are simulated by the discrete element method; the falling process is simulated by aerodynamic analysis, and the ground pattern characteristics are obtained. The model validation shows that, the numerical result agrees well with the experimental result with a maximum deviation of 14 %. The initial velocity distribution characteristic remains constant with varying filling amounts, and the mass fire firefighting units' initial velocities at different times follow a special normal distribution; the standard deviation of the initial velocities’ distribution primarily determines the width of mass firefighting units' ground pattern, while initial velocity and filling amount primarily determine the length of the ground pattern; the maximum coverage level is about 10 L/m<sup>2</sup>.</p></div>","PeriodicalId":50445,"journal":{"name":"Fire Safety Journal","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142238370","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Intercalation modified nano zirconium phosphate inhibitor for inhibiting coal spontaneous combustion 用于抑制煤炭自燃的包埋改性纳米磷酸锆抑制剂

IF 3.4 3区工程技术

Fire Safety Journal Pub Date : 2024-09-11 DOI: 10.1016/j.firesaf.2024.104265

{"title":"Intercalation modified nano zirconium phosphate inhibitor for inhibiting coal spontaneous combustion","authors":"","doi":"10.1016/j.firesaf.2024.104265","DOIUrl":"10.1016/j.firesaf.2024.104265","url":null,"abstract":"<div><p>The synthesis and characterization of a modified zirconium phosphate (MZrP) nano-inhibitor for spontaneous coal combustion inhibition were explored through isooctylamine intercalation. Using oxidation experiment, FTIR and SEM, the variation rules of the characteristic parameters of the different coal samples were investigated. It was observed that MZrP exhibited enhanced dispersion within the coal matrix post-intercalation modification. As the MZrP concentration increased, there was a notable decrease in oxygen consumption rate, gas production concentration, and active group content in the coal, alongside a significant increase in apparent activation energy and inhibition efficacy. This enhanced inhibition is attributed to two primary mechanisms. Firstly, the hydrophilic nature of MZrP allows for its uniform distribution on the coal surface and within internal pores, creating a dense carbonized layer. This layer effectively retains moisture and isolates oxygen, enhancing physical inhibition. Secondly, MZrP inhibitor is thermally decomposed into phosphoric acid and its phosphoric acid derivatives, which can effectively capture the H- and -OH in the coal, and strengthens the inactivation of its reactive free radicals. The optimal inhibition was observed in coal samples treated with 6 wt% MZrP, exhibiting an average inhibition rate of 62.2 %, coupled with the lowest rates of gas production and oxygen consumption.</p></div>","PeriodicalId":50445,"journal":{"name":"Fire Safety Journal","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142238371","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Early warning signals of flashover in compartment fires 车厢火灾中闪燃的预警信号

IF 3.4 3区工程技术

Fire Safety Journal Pub Date : 2024-09-10 DOI: 10.1016/j.firesaf.2024.104264

{"title":"Early warning signals of flashover in compartment fires","authors":"","doi":"10.1016/j.firesaf.2024.104264","DOIUrl":"10.1016/j.firesaf.2024.104264","url":null,"abstract":"<div><p>There have been efforts to predict the occurrence of flashover. Due to its sudden development and the difficulty in discerning warning signs during the induction phase, the approach to flashover prediction is still under investigation. This research tests a new approach for detecting flashover events within a compartment through single-signal processing of the heat release rate (HRR). A set of ordinary differential equations aligned with a two-zone model are formulated and transformed into stochastic differential equations, subsequently solved through a numerical method. Based on the noisy HRR readings, a dynamical marker is constructed as a product of two quantities: the smoothed HRR and the standard deviation of the noise component. The dynamical marker was found to increase prior to a rise in the HRR signal on its own, confirming its superiority as a sign of flashover detection. To assess the practical applicability of the dynamical marker, we computed it to detect flashover incidents using HRR obtained from an FDS simulation and the fire calorimetry database provided by NIST; the dynamical marker exhibited a significant rise before the transition to flashover, confirming its potential as an early warning signal.</p></div>","PeriodicalId":50445,"journal":{"name":"Fire Safety Journal","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0379711224001772/pdfft?md5=5c33e7a0d63c038e2566a4211d793665&pid=1-s2.0-S0379711224001772-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142238368","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Assessment of a PAH-based soot production model in laminar coflow methane diffusion flames doped by gasoline surrogate fuels 评估掺入汽油代用燃料的层流甲烷扩散火焰中基于多环芳烃的烟尘生成模型

IF 3.4 3区工程技术

Fire Safety Journal Pub Date : 2024-09-07 DOI: 10.1016/j.firesaf.2024.104252

{"title":"Assessment of a PAH-based soot production model in laminar coflow methane diffusion flames doped by gasoline surrogate fuels","authors":"","doi":"10.1016/j.firesaf.2024.104252","DOIUrl":"10.1016/j.firesaf.2024.104252","url":null,"abstract":"<div><p>This article assesses the capability of the PAH-based soot model developed by the authors and validated in ethylene non-premixed flames to predict soot production in flames fueled with gasoline surrogates. The soot model was coupled to a flamelet model and the Rank-Correlated Full-Spectrum k model to simulate laminar coflow nitrogen-diluted methane/air diffusion flames doped with n-heptane/toluene and iso-octane/toluene mixtures. Consistent with our previous studies, the simulation was conducted using the Kaust Mechanism 1, pyrene as soot precursor, and the same set of model parameters. The model reproduced reasonably-well the peak soot volume fraction. However, the soot production onset was predicted much earlier than measurements owing to the early formation of pyrene induced by the presence of toluene. These discrepancies can be partially corrected by selecting a larger PAH than pyrene with a similar level of concentrations as soot precursor. For the present mechanism, anthanthrene was found to be the best candidate. Model results show that different mechanisms dominate the soot mass growth in ethylene and gasoline surrogate flames. While the HACA is more important in the former, PAH condensation largely prevails in the latter. This suggests that ethylene may be not the most relevant reference fuel for developing semi-empirical soot models for fires. Further investigations are required to confirm this conjecture.</p></div>","PeriodicalId":50445,"journal":{"name":"Fire Safety Journal","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142163698","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Suppression characteristics of methane/coal dust explosions by active explosion suppression system in the large mining tunnel 大型采矿巷道中主动抑爆系统对甲烷/煤尘爆炸的抑制特性

IF 3.4 3区工程技术

Fire Safety Journal Pub Date : 2024-09-06 DOI: 10.1016/j.firesaf.2024.104251

{"title":"Suppression characteristics of methane/coal dust explosions by active explosion suppression system in the large mining tunnel","authors":"","doi":"10.1016/j.firesaf.2024.104251","DOIUrl":"10.1016/j.firesaf.2024.104251","url":null,"abstract":"<div><p>To enhance intelligent prevention and control of methane/coal dust explosions in coal mines, the active explosion suppressor was developed. Methane/coal dust explosion suppression experiments were carried out in an 896-m mining tunnel. The suppression mechanism of NH<sub>4</sub>H<sub>2</sub>PO<sub>4</sub> powder during methane/coal dust explosions was elucidated. The results indicated that the device effectively prevented flame propagation within a 40 m radius by propelling NH<sub>4</sub>H<sub>2</sub>PO<sub>4</sub> powder using high-pressure nitrogen. There was a significant reduction in the intensity and destructiveness of the overpressure, with a maximum decrease of 61.43 %. The phosphorus-containing material produced by NH<sub>4</sub>H<sub>2</sub>PO<sub>4</sub> consumed free radicals through catalytic cycles of HOPO ⇔ PO<sub>2</sub> and HOPO ⇔ HPO<sub>3</sub>⇔PO(OH)<sub>2</sub>, weakening and interrupting the reactions, and suppressing flame development. NH<sub>4</sub>H<sub>2</sub>PO<sub>4</sub> reduced peak concentrations of CO and NO<sub>2</sub>. Guidelines for explosion suppression of CH<sub>4</sub>/coal dust explosions in large mining tunnel were presented. The findings provide technical and theoretical support for the prevention and control of methane/coal dust explosions in coal mines.</p></div>","PeriodicalId":50445,"journal":{"name":"Fire Safety Journal","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142157986","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0