集中排烟隧道兼顾纵向通风和集中排烟等诸多优点，在长大隧道设计中应用广泛，如何掌握烟气在隧道内的衰减规律便于有效排烟是研究人员关注的重点。文章结合集中排烟隧道系统设计，针对50 MW大强度火灾，考虑两种火源位置，模拟预测不同送风风速v1、诱导风速v2组合工况下排风口位置烟气温度、浓度衰减规律。结果表明：火源上游排风口（1#）处烟气水平衰减系数随v1增大而减小，垂直衰减系数规律则相反，火源下游排风口（2#、3#）处烟气垂直衰减系数随v2增大而增大，水平衰减系数规律相反；各风口处烟气温度水平衰减系数大于浓度水平衰减系数，而垂直衰减系数小于浓度衰减系数，均与火源位置无关。%The central smoke extraction system is often brought into tunnel design because of the advantages of both the longitudinal ventilation and central smoke extraction . The way of mastering the decrease rate of fire smoke and smoke extraction is the focus of attention. Based on the design of a highway tunnel with central smoke extraction systems,large scale fire of 50MW has been simulated to evaluate the attenuation law of smoke temperature and concentration near vents. Five kinds of supply air velocity,five kinds of induced velocity and two fire locations are chosen in the study. According to the results,the horizontal attenuation coefficient of smoke in the upstream areas decreases with the augment of v1 ,and the vertical attenuation coefficient is opposite with that. The vertical attenuation coefficient of smoke in the downstream areas increaseses with the augment of v2 ,and the horizontal attenuation coefficient is opposite with that. The horizontal attenuation coefficient of temperature is larger than that of concentration. However,the vertical attenuation coefficient of temperature is smaller than that of concentration,and both of them are independent with fire location.
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