隧道纵向风及列车侧门开启方式对车厢内火灾温度场影响研究

Influence of tunnel longitudinal ventilation and opening mode of side door on fire temperature field in carriage

为了探究隧道纵向通风、列车侧门开启方式对车厢内部火灾烟气温度分布的影响规律,建立1∶15缩尺寸“车-隧”耦合试验模型,以及着火车厢侧门双侧开启时“车-隧”耦合区间车厢内部考虑无量纲纵向风速、无量纲侧门开口因子、无量纲火源热释放速率的无量纲烟气回流长度分段函数关系式。定性分析车厢顶部烟气温度分布规律,定量分析车厢内烟气回流长度数据,从而揭示烟气回流长度随纵向风速、侧门开启方式和火源热释放速率变化的规律。研究结果表明:不同纵向风速下,火源上游烟气温度分布在贯通门位置处发生明显降低。不同侧门开启方式下,着火车厢侧门双侧开启工况的火源上游温度衰减速率大于侧门单侧开启的工况;随着车厢每侧侧门开启数量增加,着火车厢侧门单侧开启工况与双侧开启工况的火源上游温度衰减速率差距随之增大。着火车厢、非着火车厢侧门均单侧开启时,烟气回流长度变化规律受贯通门停滞影响较大,当火源热释放速率增大至5.7 kW,纵向风速大于0.8 m/s后,烟气回流长度不再随纵向风速的增大而变化。着火车厢侧门双侧开启、非着火车厢侧门单侧开启时,烟气回流长度符合加速衰减区、停滞区、缓慢衰减区变化规律。研究结果可为提升列车火灾烟气防治效果,加强区间隧道烟气控制及运营安全提供经验和理论参考。

A 1∶15 scale“train-tunnel”coupled experimental model was utilized to investigate the impact of longitudinal ventilation and train side door opening mode on smoke temperature distribution inside a burning carriage.The qualitative analysis focused on the smoke temperature distribution at the ceiling of the carriage,while the quantitative analysis examined data on smoke back-layering length within the carriage.This aimed to reveal the correlation between smoke back-layering length and changes in longitudinal ventilation velocity,side door opening mode,and heat release rate.The research results are drawn as follows.Under different longitudinal ventilation velocities,there is a significant decrease in the temperature distribution of smoke upstream of the fire source at the through door.Moreover,when considering different side door opening modes,it is observed that the rate of temperature attenuation upstream from the fire source is higher when the side door of the burning carriage is opened on both sides compared to when the side door is open on one side.As the number of opened side doors on each side of the carriage increases,the difference in temperature attenuation rate between single-side and double-side opening modes for the burning carriage also increases.Additionally,when the side door of the burning carriage and the non-burning carriage are opened on one side,the variation of smoke back-layering length is greatly affected by the obstruction of the through door.Once the heat release rate reaches 5.7 kW and the longitudinal ventilation velocity exceeds 0.8 m/s,there is no further change in smoke back-layering length with increasing ventilation velocity.When both sides of the side doors on the burning carriage are open and only one side on the non-burning carriage is open,variations in smoke back-layering length follow a pattern of accelerating decay zone,stagnation zone,and slow decay zone.A dimensionless segmented function relationship for smoke back-layering length has been proposed,considering dimensionless longitudinal ventilation velocity,dimensionless side door opening factors,and dimensionless heat release rate within the‘train-tunnel’coupling interval.The present results can provide experience and theoretical references for improving the effectiveness of smoke control in trains,strengthening smoke control in tunnel intervals,and enhancing operational safety.