考虑人员逃生公路隧道火灾控制风速研究

公路隧道火灾人员逃生与控制风速关系密切。本研究基于PHOENICS软件,建立了矩形、圆形及马蹄形断面下二、三及四车道9种计算模型,选取了大客车(20 MW)及无载重货车(30 MW)2种火源释放率, 选取了2.0 m/s、2.5 m/s、3.0 m/s、3.5 m/s及4.0 m/s的入口风速共计40种主要常见火灾工况,考虑了纵向通风对人体极限温度承受值的影响,采用了杨涛修正的动态火源释放率曲线及周勇狄修正的克拉尼公式,选用了适当的人员逃生条件,给出了每种工况8个特征时刻的10个特征点的温度值及曲线图,给出了燃烧5 min、12 min、30 min后火源处的纵横断面温度云图及中轴面烟气云图,给出了对应于火源燃烧位置上下游8个特征位置下人员逃生的忍受时间与逃离时间。研究得出:在基于人员逃生条件下矩形断面隧道在火源释放率为20 MW时二车道控制风速为3.0 m/s,三、四车道均为2.5 m/s;30 MW时二、三、四车道控制风速均为3.5 m/s,圆形与马蹄形断面隧道在火源释放率为20 MW时二、三、四车道控制风速均为3.5 m/s,30 MW时二车道控制风速均为4.0 m/s,三、四车道均为3.5 m/s。在火灾发生1 min后,人员以1 m/s从火源上下游进行疏散均可安全逃生。

Study on the Control of Ventilation Velocity of Fire in Highway Tunnel Based on the Safety Evacuation

The safety evacuation of highway tunnel fire is closely related to the control of ventilation velocity. Based on the PHOENICS software, 9 kinds of calculation models of two, three and four lanes under rectangular, circular and horseshoe cross sections were established. 2 kinds of fire rate of bus(20 MW)and no-load truck(30 MW)were selected. The inlet wind speed of 2.0 m/s, 2.5 m/s, 3.0 m/s, 3.5 m/s and 4.0m/s were considered, and 40 main common fire conditions were considered totally, taking into account the effects of longitudinal ventilation on temperature limit value of human body. Yangtao’s revised dynamic HRR curve and ZhouYongdi’s revised Krani formula were used, and appropriate personnel evacuation conditions were adopted. 10 characteristic temperature values and curves at 8 characteristic moments of each working condition were given. The temperature and smoke pattern of the vertical and horizontal cross-section of the fire at 5 min, 12 min and 30 min after combustion were given, and the tolerance time and the evacuation time of the safety evacuation were obtained under the 8 characteristic positions of the upstream and downstream of the fire burning position. The research results show that the control of ventilation velocity of the two-lane rectangular section tunnel is 3.0 m/s when the HRR is 20MW, 2.5 m/s for three and four lanes, and the velocities of the two-lane、three-lane、four-lane rectangular section tunnel are 3.5 m/s when the HRR is 30 MW; the control of ventilation velocity of the two-lane、three-lane、four-lane circular and horseshoe cross sections tunnel is 3.5 m/s when the HRR is 20 MW, 4.0 m/s for the two-lane and 3.5 m/s for the three and four lanes when the HRR is 30MW. After the fire occurred 1min, the personnel can be evacuated from the upstream and downstream of the fire source with the speed of 1m/s safely.