隧道火灾中重点排烟的排烟量及排烟口布置

Smoke Exhaust Rate and Exhaust Vent Distribution of the Point Exhaust System in Tunnel Fire

排烟量和排烟口布置是隧道重点排烟中影响烟气控制效果的关键因素.采用数值模拟的方法研究不同火源功率及不同隧道宽度时火灾烟气的生成量,并依据烟气生成量研究不同排烟量、不同排烟口布置对隧道内烟气蔓延长度和排热效率的影响.研究结果表明,烟气的生成量与火源功率、隧道宽度以及烟气的蔓延长度密切相关.当前规范中推荐的排烟量难以达到《公路隧道通风设计细则》中建议的300 m的烟气控制目标.若以烟气的控制范围为排烟系统的设计目标,烟气的控制范围和排烟口的开启范围之间存在线性关系,设计中可依此优化排烟口的布置.

The smoke exhaust rate and the arrangement of the exhaust vents are the key factors that can affect the smoke control effect in tunnel fire.The smoke production rate with different heat release rates and different tunnel widths was studied by a numerical method.The effects of different smoke exhaust rates and the distribution of the exhaust vents on the smoke spreading length and the heat exhaust efficiency were also investigated.Results show that the smoke production rate is closely related to the heat release rate of the fire source,the width of the tunnel and the length of smoke spread.It is difficult to control the smoke within the length of 300 m which is suggested in the“Guidelines for Design of Ventilation of Highway Tunnels”using the recommended smoke exhaust rate in the relative tunnel design codes.If the design objective is to control the smoke in a certain range,there is a linear relationship between the control range of smoke and the opening range of the exhaust vent,and the distribution of the exhaust vent can be optimized following the relationships.