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建立1∶20的缩尺寸隧道模型,以研究隧道集中排烟速率对烟气层吸穿现象的影响。分析对称开启的6个排烟口,排烟速率由0.045 m3/s逐渐增大到0.179 m3/s时,排烟口下方烟气层蔓延范围、厚度和温度的变化规律。在不同排烟速率下,邻近火源的排烟口L1和R1均未发生吸穿现象;而远离火源的排烟口L3和R3排出的几乎为空气;在排烟速率为0.112~0.179 m3/s时,处于中间位置的排烟口L2和R2发生吸穿过渡现象,后随排烟速率增大则发生完全吸穿现象。结果表明:当隧道集中排烟速率不断增大时,排烟口下方烟气层逐渐发生吸穿现象,且距火源越远的排烟口越容易发生吸穿现象。
A 1: 20 scale tunnel model was established to study the effect of tunnel exhaust rate on the flue gas layer suction. The variation of flue gas layer spreading range, thickness and temperature under the exhaust port was analyzed when the exhaust velocity increased from 0.045 m3 / s to 0.179 m3 / s. At different flue gas emission rates, there was no suction of L1 and R1 in the exhaust ports adjacent to the source of fire, while the almost exhausted air in the exhaust ports L3 and R3 far away from the source of fire was discharged at a rate of 0.112-0.1779 m3 / s, in the middle of the exhaust port L2 and R2 suction transition phenomenon occurs, with the exhaust rate increases after the phenomenon of complete absorption occurs. The results show that when the concentration of smoke in the tunnel increases continuously, the suction layer gradually takes place under the exhaust port, and the suction port which is farther away from the ignition source is more likely to get through.