侧部重点排烟与水喷淋协同作用下隧道烟气运动研究

合理的水喷淋设计参数及排烟策略,可保证隧道有效排烟和烟气层的稳定性,为人员安全疏散提供有利环境。为研究侧部排烟模式下烟气失稳临界状态时最佳喷水流量和排烟口设计参数,采用FDS对15MW火灾规模下,不同喷水流量、排烟量、排烟口间距及排烟口高度下19组工况进行模拟计算。结果表明:喷淋流量越大,烟气层高度越高,隧道整体温度降低,改变喷水流量对控制烟气层的稳定性效益不大,隧道空间内有烟气滞留;排烟量为70m3/s、排烟口间距为50m、排烟口高度为3.2m或4.0m为烟气层稳定临界状态时的排烟口最佳参数,此时侧部抽吸力向上的分力与烟气的热浮力大于水喷淋拽曳力,烟气层较稳定,隧道空间内无旋涡烟气滞留,有利于排烟和人员疏散。

Study on the effect of water spray on smoke layer stability under side exhaust mode in tunnels

Reasonable water spray design parameters and smoke exhaust strategy can ensure the effective smoke exhaust and smoke layer stability of the tunnel, and provide a favorable environment for the safe evacuation of personnel. In order to study the optimal water spray flow rate and smoke vent design parameters when the smoke loses the stable critical state in the side smoke exhaust mode, FDS was used for a 15 MW fire scale with different water spray flow rate, smoke exhaust volume, distance or height of smoke exhaust vent. 19 groups of working conditions with different spray flow, smoke exhaust flow, distance or the height of the smoke exhaust port are simulated and calculated. The results show that: the greater the spray flow, the higher the height of the smoke layer, the lower the overall temperature of the tunnel, and the change of the spray flow has a little effect on the stability of the smoke layer, there is smoke retention in the tunnel space. The smoke exhaust port is 70 m3/s, the exhaust port spacing is 50 m, and the exhaust port height is 3.2 m or 4.0 m, which is the best parameter of the exhaust port when the smoke layer is in a critical state. At this time, the side suction force upward component and the thermal buoyancy is greater than the drag force of the water spray, the smoke layer is relatively stable, and there is no swirling and smoke retention in the tunnel space, which is beneficial for smoke exhaust and personnel evacuation.