不同受限条件下综合管廊电缆桥架火灾烟气温度分布特性研究  

Experimental study on the smoke temperature distribution of cable tray fires of utility tunnel under different entrainment restriction conditions

作　　者：黄萍[1] 林煦东 刘春祥 曾凡捷 林开虹 杨明理 余龙星 HUANG Ping;LIN Xudong;LIU Chunxiang;ZENG Fanjie;LIN Kaihong;YANG Mingli;YU Longxing(College of Environmental and Safety Engineering,Fuzhou University,Fuzhou 350108,China)

机构地区：[1]福州大学环境与安全工程学院,福州350108

出　　处：《安全与环境学报》2024年第3期897-906,共10页Journal of Safety and Environment

基　　金：福建省科技厅青创基金项目(2022J05123);国家自然科学青年基金项目(52006210)。

摘　　要：为了更有效地防控综合管廊电缆桥架火灾,在全尺寸综合管廊中开展了电缆桥架火灾试验,系统研究了电缆层数和卷吸条件对电缆桥架火灾烟气温度分布的影响。在电缆桥架附近垂直和水平布置一系列热电偶,分别用于测量管廊内垂直和顶棚水平温度分布。基于管廊内的垂直温度分布,揭示了火灾场景下管廊垂直温度分层规律。结果表明,管廊内发生电缆桥架火灾时,管廊内从上往下可以分为三部分:顶部射流层、中间热烟气过渡层和下部冷空气层。通过分析管廊不同端口的顶棚横向温度分布,发现顶棚温度在半封闭端的衰减速度比全封闭端更快,建立了考虑热释放速率和火源距离顶棚距离的全封闭端顶棚下方无量纲纵向温度分布模型。最后根据卷吸条件与顶棚最大温升的对应关系,发现整体火源功率越大的电缆桥架火灾受到侧壁和端壁的热反馈影响越强烈,针对不同卷吸条件下的电缆桥架火灾分别建立了顶棚最大温升预测模型。通过将模型预测值与试验值对比,发现模型误差在16%以内。In order to enhance the prevention and control of cable tray fires in utility tunnels,this study conducted a full-scale cable tray fire test and systematically investigated the influence of the number of cable layers and the effects of entrainment restriction on the distribution of smoke temperature in cable tray fires.A series of thermocouples were placed both vertically near the cable tray fires and horizontally beneath the ceiling to measure the vertical and horizontal temperature distribution of the utility tunnel.Based on the vertical temperature distribution in utility tunnels,the vertical temperature stratification patterns caused by the settling of smoke from cable tray fires in utility tunnels were revealed.Results show that,when cable tray fire happens,the utility tunnel can be divided into three parts from top to bottom:the top jet layer,the middle hot smoke transition layer,and the bottom cold air layer.By analyzing the transverse smoke temperature distribution beneath the ceiling at different ports of the utility tunnel,it is found that the rate of temperature decay at the semi-closed end is faster than that at the fully closed end.Additionally,a dimensionless longitudinal temperature distribution model,considering the heat release rate and the effective source-ceiling height,was established for the fully enclosed end roof.Finally,based on the relationship between the air entrainment restriction and the maximum temperature rise beneath the ceiling,it is found that the cable tray fire is significantly influenced by the thermal feedback from the side wall and end wall when the overall ignition source power is higher.A prediction model was developed for the maximum temperature rise of the roof in cable tray fires,considering the restrictions on air entrainment from the sidewall.By comparing the model’s predictions with the experimental results,it is found that the model error was less than 16%.Findings of this study provide guidance for the fire prevention of cable tray fires in utility tunnel.

关 键 词：安全工程 综合管廊 电缆桥架火灾 烟气温度分布 卷吸受限 

分 类 号：X931.4[环境科学与工程—安全科学]