地下立交互通匝道集中排烟效果研究

Study on the Effect of Centralized Smoke Exhaust from Underground Interchange Ramps

针对两端连接主隧道的互通匝道火灾烟气控制问题,依托南京建宁西路曲线A匝道工程,借助数值模拟软件FDS,研究HRR为30 MW下纵向诱导风速、排烟口尺寸及火源位置对顶部集中排烟效果的影响。结果表明:火源位于匝道中部,诱导风速为1.0 m/s时恰好保证烟气不发生“跨区蔓延”,诱导风速为1.5 m/s、排烟量为150 m^(3)/s时,控烟效果更好;匝道内烟气蔓延范围随排烟口尺寸增大而减小,当排烟口长宽比为4、面积为6 m^(2)时,匝道内烟气控制效果较好,系统整体排烟效率大于98%;排烟口长宽比不变时,拱顶最高温度随排烟口面积增大而降低;排烟口面积不变时,拱顶最高温度随排烟口长宽比增大而升高。火源位于匝道上游或下游时,排烟风量至少需增大至210 m^(3)/s,诱导风速需作针对性优化。

For the fire smoke control of the interchange ramp connecting the main tunnel at both ends,the effect of the longitudinal induced air velocity,smoke vent size and fire source location on the top centralized smoke exhaust effect was investigated with the help of numerical simulation software FDS based on the Nanjing West Jianning Road Curve A ramp project.The results show that:the fire source is located in the middle of the ramp,the induced air speed is 1.0 m/s to ensure that the smoke does not"spread across the area",and the smoke control effect is better when the induced air speed is 1.5 m/s and the smoke volume is 150 m^(3)/s;the smoke spread range in the ramp decreases with the increase of the smoke vent size,and when the smoke vent length to width ratio is 4 and the area.When the smoke vent aspect ratio is 4 and the area is 6 m^(2),the smoke control effect in the ramp is better,and the overall smoke exhaust efficiency of the system is more than 98%;when the smoke vent aspect ratio is unchanged,the maximum temperature of the vault decreases with the increase of the smoke vent area;when the smoke vent area is unchanged,the maximum temperature of the vault increases with the increase of the smoke vent aspect ratio.When the fire source is located in the upstream or downstream of the ramp,the smoke exhaust air volume should be increased to at least 210 m^(3)/s and the induced air velocity should be optimized.