深井“T”型巷道火灾的安全区域划分

Classification of safety zones for T-shaped roadway fire in deep coal mines

矿井火灾中高温烟气的流动扩散是造成安全事故的重要原因,针对矿井典型巷道中火灾危险区域与时间关系不明确的问题,提出了一种深井“T”型巷道火灾的安全区域划分方法。采用Pyrosim软件建立三维数值模型,模拟了在高温高湿情况下“T”型巷道火灾发展阶段巷道内的高温烟气流动,揭示了火灾发展阶段“T”型巷道下温度场和有害气体浓度场随时间和空间位置的变化规律;根据人体口鼻高度(即巷道1.6 m高度位置)的模拟数据,得出巷道的水平长度与温度、CO浓度、CO_(2)浓度的关系:风流通过巷道混合高温烟雾沿巷道顶部向下风侧蔓延,随着与火源距离增加,温度逐渐降低,CO、CO_(2)浓度等值线纵向分布逐渐密集。在此基础上,根据烟气温度和CO、CO_(2)气体对人体的危害程度进行安全区域划分,将烟气扩散区域划分为安全区域(危险等级1)、轻度危险区域(危险等级2)、中度危险区域(危险等级3)、重度危险区域(危险等级4)4类,分析结果表明:温度划分结果中巷道Ⅰ中测点主要集中在重度危险区域,毒性气体划分结果中巷道ⅠCO_(2)的安全区域范围较CO大,CO的危险因素更大,主要集中在轻度、中度危险区域,在巷道Ⅱ中测点主要集中在轻度危险区域;在巷道Ⅰ中危险等级1的范围随时间的推移逐渐变小,危险等级4的范围随时间的推移逐渐变大,且均在40 s时变化率最大,危险等级2、3变化率很小;在巷道Ⅱ中2种划分方法的区域范围变化相似,危险等级2、3均在60 s时变化率最大。

The flow and diffusion of high-temperature smoke in mine fires is an important cause of safety accidents.In response to the unclear relationship between fire hazard zones and time in typical mine roadways,a safety zone classification method for T-shaped roadway fire in deep coal mines is proposed.A three-dimensional numerical model is established using Pyrosim software to simulate the high-temperature smoke flow in the Tshaped roadway during the fire development stage under high temperature and humidity conditions.The variation law of temperature field and CO,CO_(2) concentration field with time and spatial location in the T-shaped roadway during the fire development stage are revealed.Based on the simulated data of the height of the human mouth and nose(i.e.the height of 1.6 meters in the roadway),the relationship between the horizontal length of the roadway and temperature,CO concentration and CO_(2) concentration is obtained.The airflow mixes high-temperature smoke through the roadway and spreads downwards along the top of the roadway.As the distance from the fire source increases,the temprature gradually decreases,and the longitudinal distribution of COand CO_(2) concentration contour lines becomes denser.On this basis,safety zones are classified based on the temperature of the smoke and the harm degree of CO and CO_(2) concentration to human health.The smoke diffusion area is divided into four categories:safety zone(hazard level 1),mild hazard zone(hazard level 2),moderate hazard zone(hazard level 3),and severe hazard zone(hazard level 4).The analysis results show that in the temperature classification results,the measurement points in roadway Ⅰ are mainly concentrated in the severe hazard zone.In the toxic gas classification results,the safety zone range of CO_(2) in roadway Ⅰ is larger than that of CO.The risk factors for CO are greater,mainly concentrated in mild and moderate hazard zones.In roadway Ⅱ,it is mainly concentrated in mild hazard zones.The range of hazard level 1 in roadway Ⅰ gradually decreases over time,while the range of hazard level 4 gradually increases over time,with the maximum change rate occurring at 40 seconds.The rates of change for hazard levels 2 and 3 are very small.The regional range changes of the two classification methods in roadway Ⅱ are similar,with the maximum change rate of hazard levels 2 and 3 occurring at 60 seconds.