Coal mine fire and human escape simulation

Coal mine fire and human escape simulation system is developed based on 3D Max and EON software for the purpose of coal mine safety training.The models,such as miners,roadways,typical equipments,fire and smoke are all constructed in 3D Max.The roadway models derived from real data,functions of each part are determined for the roadway based on the data,and then corresponding tunnel typical equipments are added.Emergency refuge system model is not only an important system model,but also an important destination for fire simulation and human escape.The roaming of the miners through the roadways,the interactive functions between users and computer,the fire process of beginning,spreading,and destroying,the human escape interaction are simulated in EON virtual reality software after these models have been input into it.Besides,collision detection based on hierarchical bounding volumes is also utilized.Simulation results suggest that this strategy can produce realistic virtual state and fire effect.While as part of the coal mine safety simulation and training System(CMSSTS),this work is far from what we expected,and there is more intensive work that should be done.

A Review on Mine Fire Disasters and Assessment of Fire Detection Using a Dual-Cab Suppression System

The health and productivity of mining operations are negatively impacted by coal mine fires, making them dangerous. It happened everywhere, in both working and abandoned coal mines. This study seeks to review and provide technical analytics of potential mine fires and fire detection in a Dual-Cab suppression system. Analysis was done on potential mine fires like spontaneous combustion, flammable gas explosions, and cab vehicle fires. Additionally, a review of the NIOSH experiment was conducted to assess the performance of smoke and flame detectors in a dual-cab suppression system. This study guides both open-pit and underground mining operations. Additionally, a few ideas and suggestions are presented to assist with on-the-job safety analysis, ensuing creative alterations, and technology advancement for the mining industry’s overall safety.

Theoretical analysis and applications of Y-Inversion Ventilation System in a mine fire zone

Based on mine fire fighting practices at the 1110 working face of the Brapukuria Coal Mine,Bangladesh,we introduce and discuss the Y-Inversion Ventilation System,the latest technology used both in mine fire zone management and the unsealing process.This ventilation system can ensure that all miners breathed fresh air,providing protection for them during fire fighting and unsealing the fire zone.On the other hand,adjusting the amount of air at the working face and forming a CO leakage path controlled the state of the fire and as well ensured that the different fire extinguishing measures could be applied successfully.These are all fundamental techniques which ensured successful fire extinguishing and unsealing of the fire zone.We also analyzed the main reasons for the spontaneous coal combustion that occurred at the 1110 working face.Successful application of advanced composite polymer colloidal perfusion techniques,polymer foam MEA perfusion and fire-prevention technology by infusing nitrogen,used in mine fire zone management and unsealing,are presented.We value the experience with these techniques very highly and are of the opinion that these techniques could be widely used in mine fire fighting practices under similar spontaneous coal combustion conditions elsewhere.

Experimental Study on Airflow Reversal Within Bypass Branch During Mine Fire

Based on the analysis of conditions for airflow reversal within a bypass branch, the airflow reversal phenomena were successfully simulated in the laboratory experiments. Data obtained indicate that airflow reversal within a bypass branch is mainly caused by fire pressure yielded in the combustion branch. In addition, the maximum reversal quantity of airflow occurs in step with the highest temperature of fire, the highest concentration of CO 2 and the lowest concentration of O 2. Moreover, the time that fire size reaches the maximum value corresponds to the time airflow reversal in the bypass branch is most possible. The results are of great significance for guiding rescue work to avoid airflow reversal.

Chaos dynamic characteristics during mine fires

Mine fires break out and continue in confined scopes, studying mine fire dynamics characteristics is very useful to prevent and control fire. The judgement index of fire chaos characteristics was introduced, chaos analysis of mine fire process was described, and the reconstruction of phase space was also presented. An example of mine fire was calculated. The computations show that it is feasible to analyze mine fire dynamic characteristics with chaos theory, and indicate that fire process is a catastrophe, that is to say, the fire system changes from one state to another during mine fire.

THE COMBUSTION CHARACTERISTICS OF A MOVABLE LINEAR FIRE SEAT IN MINE FIRES

Because of the difficulties of describing the process of combustion of underground mine fires, usually the fire seat is considered as a fixed point in the methods of mine fire computer simulation, however this is not in keeping with the feature of the distribution of the combustibles and the process of combustion in mine fires. A conception about movable linear fire seat is put forward first by the authors, together with the calculated models of the thermal decomposition rate, flame spreading velocity and the steady burning length of a linear fire seat etc. The paper also introduces the results of the application of these models.

Computer simulation of combustion of mine fires

According to control theories, mine fires can be considered as an unsteady process after the normal ventilation system is disturbed. Applied the principal of physical chemistry and thermal fluid mechanics, the parameters models of the unsteady state system have been given, such as fuel combustion rate, heat of combustion, concentration, temperature, heat losses, heat resistance, work of expansion and heat pressure difference. The results of the calculation agree approximately with the results of the test. By the computer simulation, it is shown that the main factor of producing the throttling effect is the fire rate, second is the heat resistance and the heat pressure difference. The rate of heat flow that passes through the airway wall is the maximum on the surface, and decrease with time. The heat transfer progresses only within the range of 0.5 m away from theairway wall during combustion for 2 hours. It’s variable for the mass flux rate and the percentage concentration of the gas along the airway of the downstream. When the delayed time is very small, the variation can be neglected. Viscosity resistance is the main part of the heat resistance, second is the expansion resistance that is less than tens Pascal when Mach number is very small. Work of expansion is principally turned into heat losses, only a very small part is consumed by the work of the heat resistance and the inertia acceleration.

STUDY ON THE COMBUSTION CHARACTERISTICS OF MINE FIRES

Based on the distribution state of the combustibles and the scale of the fires in underground mines, mine fire sources are divided into two types in this paper,namely, fixed point fire source and movable linear fire source. By analying a lot of ex periment results of mine fires, the authors studied the combustion characteristics of the two types of fire source, and have set up their mathematical models. The models have further been applied to calculate the concrete mine instances and the obtained re sults corresponded with the reality.

Practice of Fighting Fire and Suppressing Explosion for a Super-Large and Highly Gassy Mine

The Baijigou Mine fire in Ningxia Province,which broke out on October 24,2003,affected more than 108 m3 of the mine and was probably the largest underground fire in China in recent years. In addition to its size,the fire was also characterized by excessive air leakage and the potential for violent methane explosions. A series of new measures were taken to fight the fire,including sealing intake tunnels with water,injecting three-phase foam through boreholes,and flushing with a large volume of nitrogen. The fire was successfully extinguished and production re-sumed soon afterwards; not one single methane explosion occurred during fire-fighting and afterwards.

Fire behaviour of multiple fires in a mine drift with longitudinal ventilation

The fire behaviour involving multiple fires in a mine drift with longitudinal ventilation was analysed. The conditions and fire phenomena occurring were described. The analysis was based upon experimental data from model-scale fire experiments. A fire involving several fuel items may lead to flames tilted horizontally and filling up the entire cross section, leading to earlier ignition, higher fire growth rates, higher fire spread rate and severe fire behaviour. Longer flame lengths will also result due to decreased air entrainment. A correlation for the continuous flame length was proposed. The results of the analysis will help identifying and preventing potentially dangerous fire situations with several large combustible items distributed along a mine drift.

Fire behavior of mining vehicles in underground hard rock mines

The results from a number of investigations and fire experiments are presented and analyzed in order to characterize the fire behavior of mining vehicles in underground hard rock mines. The analysis also includes fire safety and fire protection measures with respect to the mining vehicle fire behavior.Earlier studies on fires in underground hard rock mines have shown that vehicles or mobile equipment are the dominant sources of fire. A better knowledge about the fire behavior of vehicles in underground hard rock mines is therefore needed. During the analysis the direction and flow rate of the ventilation in a drift was found to have a significant impact on the fire behavior, causing for example flame tilt with rapid fire spread. The shielded sections of a vehicle will be less affected by the ventilation flow resulting in for example a decreased flame spread. It was also found that spray fires may result in considerable heat release rate but are generally of shorter duration and will not make any significant contributions to the overall heat release rate of the fully developed vehicle fire. The fire duration of a loader tire from a full-scale fire experiment was found to be at least 200 min and will largely determine the total fire duration of the vehicle. A different scenario with different conditions with for example a slower flame spread resulted in an even longer fire duration. The radiative and convective fraction will be a key factor when determining the heat transfer mechanisms involved in a fire and will vary from material to material.Calculations show that the radiative fraction of the tire fires on two mining vehicles is significantly lower than found in earlier experiments. The design and construction of the mining vehicle will have an important impact on the fire behavior and could possibly mitigate the consequences of a fire and allow fire personnel to extinguish a fire that otherwise would have had a too high heat release rate.

FIELD-NETWORK MODEL FOR MINE FIRE SMOKE MOVEMENT

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基于Unity3D的矿井火灾监测与防治虚拟仿真试验系统

为更好地开展矿业安全类专业试验实践教学和培训,培养安全应急一流复合型拔尖人才,设计一种基于Unity3D的矿井火灾监测与防治虚拟仿真试验教学系统。首先,采用3ds Max建立仿真模型,构建矿井火灾监测防治试验系统总体框架;其次,开展外因火灾监测与远程自动控制救灾风门应急处置、内因火灾监测与温控胞衣阻化剂防灭火应急防控等人机交互试验实训;最后,建立综合评测的试验评价体系用于考核评估。结果表明:该试验系统具备虚拟现实沉浸性、交互性、构想性的技术特点,利于打造井下三维虚拟仿真场景,逼真展示矿井火灾演变过程;在试验与实训方面,可以突破传统模式在时间、空间、安全、资源等方面的限制,提供自主学习与多元评价方式。

矿井火灾智能监测预警技术近20年研究进展及展望

为加强矿井火灾智能监测预警系统建设,提出了矿井火灾智能监测预警技术研究思路,从矿井火灾智能感知技术及装备、预测技术及模型、智能预警系统及平台3方面综述了矿井火灾智能监测预警技术研究进展。首先,总结了内外因火灾信息监测技术及装备,归纳了基于图像视频识别的识别流程,阐述了多源信息融合在火灾监测过程中的应用情况。其次,介绍了矿井火灾的预测技术及模型,包括支持向量机、人工神经网络、随机森林算法等机器学习算法。然后,阐述了矿井火灾预警系统及平台:在总结矿井煤自燃和外因火灾分级预警技术的基础上,介绍了矿井火灾预警系统平台的感知层、网络层、服务融合层以及应用层方面的进展内容;归纳了预警系统各层的内涵及应用框架;搭建了矿井火灾智能监测预警系统。最后,展望了我国矿井火灾智能监测预警技术的未来发展趋势,具体包括:在矿井火灾信息智能感知技术方面,提出加强传感技术及装备研发;在矿井火灾智能预测技术方面,提出加强隐蔽火源的位置探寻方法研究,构建火灾灾害透明化模型;在矿井火灾智能预警系统建设方面,提出将大数据融入智能判识,查明矿井火灾风险源及隐蔽火源位置的预报,实现特殊条件下煤自燃的预警。在矿井火灾智能判识与防控技术联动方面,提出利用大型语言模型在智能判识的基础上实现对矿井火灾的自适应防控。

细水雾与纵向通风对倾斜巷道火灾烟气运动规律影响研究

为了解决倾斜巷道火灾期间高温毒害烟气严重威胁井下人员避灾和救援等问题,采用Fluent数值模拟和1∶20缩尺火灾实验的方法,对不同巷道坡度下的烟气运动和温度变化进行研究。研究结果表明:添加细水雾和纵向通风都会降低倾斜巷道火灾温度。对于细水雾,下游顶板温度随着巷道坡度的增大而减小;对于纵向通风,控烟降温效果随巷道坡度的增大而降低。研究结果可为倾斜巷道防排烟设计以及对火灾下风侧烟气蔓延控制和救援提供参考。

基于Transformer的矿井内因火灾时间序列预测方法

传统的基于机器学习的矿井内因火灾预测方法尽管具备一定的预测能力,然而在处理复杂的多变量数据时不能有效捕捉数据间的全局依赖关系,导致预测精度较低。针对上述问题,提出了一种基于Transformer的矿井内因火灾时间序列预测方法。首先,采用Hampel滤波器和拉格朗日插值法对数据进行异常值检测和缺失值填补。然后,利用Transformer的自注意力机制对时间序列数据进行特征提取及趋势预测。最后,通过调节滑动窗口的大小与步长,在不同的时间步长和预测长度下对模型进行不同时间维度的训练。结合气体分析法将矿井火灾产生的标志性气体(CO,O_(2),N_(2),CO_(2),C_(2)H_(2),C_(2)H4,C_(2)H_(6))作为模型输入变量,其中CO作为模型输出的目标变量,O_(2),N_(2),CO_(2),C_(2)H_(2),C_(2)H4,C_(2)H_(6)作为模型输入的协变量。选取陕煤集团柠条塔煤矿S1206回风隅角火灾预警的束管数据进行实验验证,结果表明:①对CO进行单变量预测和多变量预测,多变量预测相比单变量预测有着更高的预测精度,说明多变量预测能通过捕捉序列间的相关性提高模型的预测精度。②当时间步长固定时,基于Transformer的矿井内因火灾预测模型的预测精度随着预测长度的增加而下降。当预测长度固定时,模型的预测精度随时间步长增加而提高。③Transformer算法的预测精度较长短时记忆(LSTM)算法和循环神经网络(RNN)算法分别提高了7.1%~12.6%和20.9%~24.9%。

矿井U型工作面火灾烟流危险性控制的模拟分析

为研究局部反风和自动喷淋系统在矿井工作面灾后有效降低烟流危险性的效果,采用FDS软件模拟某煤矿“U”型通风工作面进风侧发生火灾时,风门局部反风、正常通风和自动喷淋系统联动及局部反风和自动喷淋共同作用3种工况下矿井工作面危险因素的变化规律。研究结果表明:仅加入自动喷淋系统时火源点附近温度降幅在20℃左右,能见度、CO_(2)气体体积分数均无显著变化;反风导致风流紊乱,进风侧温度急剧升高,反风的同时加入自动喷淋系统可使得工作面入风侧最高环境温度降幅达100℃,稳态环境温度降低40℃;风门局部反风、火源功率为1 MW时,灾后在180~300 s内采取反风措施最有利于作业人员的疏散;风门局部反风、火源功率为2 MW时,灾后在240 s前采取反风措施最有利于作业人员的疏散。综上,采用风门局部反风和自动喷淋系统联动措施确能更好地控制工作面的烟流危险性,在此基础上提出风门局部反风措施的最佳时间区间。研究结果可为同类型矿井工作面火灾烟流危险性控制提供参考。