纵向通风水平隧道火区阻力特性

Flow Resistance Characteristics of Fire Zone in Horizontal Tunnel with Longitudinal Ventilation

通过建立风流与火源的统一控制体,分析了纵向通风水平隧道火区通风阻力的构成,建立了火区阻力特性的计算模型．结果表明:火区阻力包括摩擦阻力和加速阻力两部分;在火区长度较大时,摩擦阻力将成为火区阻力的主要部分;在火区长度较小时,加速阻力将成为火区阻力的主要部分;忽略烟气质量的增加及组分的变化会导致火区温度计算结果过高,进而可能造成火区通风阻力计算结果的明显升高．

By defining a control volume containing all the fire, smoke and air flow in fire zone, the mechanism of flow resistance of the fire zone in horizontal tunnel with longitudinal ventilation was analyzed, and a theoretical model for calculating the fire zone＇s flow resistance was proposed. The results show that the flow resistance of fire zone consists of frictional resistance and acceleration resistance. The frictional resistance can be more dominant than acceleration resistance for a longer fire zone, and acceleration resistance can be more dominant for a shorter one. Omitting the mass increase and content variation of smoke flow will lead to overestimate the fire zone＇s temperature, and then overestimate the fire zone＇s flow resistance.