城市浅埋隧道竖井排烟烟气逆流的影响研究
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摘要
为研究浅埋隧道中烟气逆流长度的影响因素,以武汉东湖隧道为工程背景,采用量纲分析法,构建竖井排烟隧道内火源上游烟气逆流长度无因次表达式,并通过数值模拟,量化研究火源热释放速率、纵向送风风速、竖井与火源距离、竖井宽和高对火源上游烟气逆流的影响。结果表明:上游烟气逆流长度随火源热释放速率、竖井与火源距离增长而增大,但当超过一定值时,烟气逆流长度均趋于稳定;随着隧道纵向风速和竖井宽度的增加而减小,且不受竖井高度变化的影响;同时,火源热释放速率与纵向风速的影响明显强于其他因素。创新性推导出了考虑火源热释放速率、纵向送风风速、竖井与火源间距、竖井宽度情况下火源上游无量纲烟气逆流长度的预测公式,且与数值模拟结果良好吻合。
In order to explore the influence of vertical smoke exhaustion shaft of urban shallow tunnel on smoke back-layering flow at upstream of the fire source, dimensional analysis method is used to establish the dimensionless expression of smoke back-layering flow at upstream of the fire source in Donghu Tunnel with vertical smoke exhaustion shaft; and numerical simulation method is used to study the influences of the heat release rate(HRR), longitudinal ventilation velocity, distance between shaft and fire source and the width and height of the shaft on upstream smoke back-layering flow. The results show that:(1) The upstream smoke back-layering flow length increases with the increase of HRR and the distance between the shaft and the fire source, and it becomes stable when reaches a certain value.(2) The upstream smoke back-layering flow length decreases with the increase of tunnel longitudinal ventilation velocity and shaft width;(3) The shaft height does not affect the upstream smoke back-layering flow length.(4) The HRR and the horizontal ventilation velocity affect the upstream smoke back-layering flow length more obviously than other factors. Moreover, a formula is innovatively deduced to predict the dimensionless smoke back-layering flow, which comprehensively considers the effects of the HRR, longitudinal ventilation velocity, distance between shaft and fire source and shaft width, and whose results are coincide with the numerical simulation results well.
In order to explore the influence of vertical smoke exhaustion shaft of urban shallow tunnel on smoke back-layering flow at upstream of the fire source, dimensional analysis method is used to establish the dimensionless expression of smoke back-layering flow at upstream of the fire source in Donghu Tunnel with vertical smoke exhaustion shaft; and numerical simulation method is used to study the influences of the heat release rate(HRR), longitudinal ventilation velocity, distance between shaft and fire source and the width and height of the shaft on upstream smoke back-layering flow. The results show that:(1) The upstream smoke back-layering flow length increases with the increase of HRR and the distance between the shaft and the fire source, and it becomes stable when reaches a certain value.(2) The upstream smoke back-layering flow length decreases with the increase of tunnel longitudinal ventilation velocity and shaft width;(3) The shaft height does not affect the upstream smoke back-layering flow length.(4) The HRR and the horizontal ventilation velocity affect the upstream smoke back-layering flow length more obviously than other factors. Moreover, a formula is innovatively deduced to predict the dimensionless smoke back-layering flow, which comprehensively considers the effects of the HRR, longitudinal ventilation velocity, distance between shaft and fire source and shaft width, and whose results are coincide with the numerical simulation results well.
引文
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[5] LI Y Z, LEI B, INGASON H. Study of critical velocity and back-layering length in longitudinally ventilated tunnel fires[J]. Fire Safety Journal, 2011, 45(6/8): 361.
[6] CHEN L F, HU L H, TANG W, et al. Studies of buoyancy driven two-directional smoke flow layering length with combination of point extraction and longitudinal ventilation in tunnel fires[J]. Fire Safety Journal, 2013, 59(7): 94.
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[9] TAKEUCHI S , AOKI T , TANAKA F , et al. Modeling for predicting the temperature distribution of smoke during a fire in an underground road tunnel with vertical shafts[J]. Fire Safety Journal, 2017, 91: 312.
[10] GUO Q H , ZHU H H , YAN Z, et al. Experimental studies of the gas temperature and smoke back-layering length of fires in a shallow urban road tunnel with large cross-sectional vertical shafts[J]. Tunnelling & Underground Space Technology, 2019, 83: 565.
[11] 孙振东.因次分析原理[M].北京: 人民铁道出版社, 1979.SUN Zhendong. Principle of dimensional analysis[M]. Beijin: People′s Railway Publishing House, 1979.
[12] BAUM H R. Private communications[M]. Maryland:[s.n.], 2000.
[13] 祝实, 霍然, 胡隆华, 等. 网格划分及开口处计算区域延展对 FDS 模拟结果的影响[J]. 安全与环境学报, 2008, 8(4): 131.ZHU Shi, HUO Ran, HU Longhua, et al. Influence of mesh grid and computational domain on FDS simulation[J]. Journal of Safety and Environment, 2008, 8(4): 131.
[14] MCGRATTAN K, MCDERMOTT R, HOSTIKKA S, et al. Fire dynamics simulator version 5 [J]. National Institute of Standards and Technology Special Publication, 2010, 1019(5): 222.
[15] LIN C J, CHUAH Y K. A study on long tunnel smoke extraction strategies by numerical simulation[J]. Tunnelling and Underground Space Technology, 2008, 23(5): 522.
[16] 李颖臻, 雷波. 隧道火灾模型试验中列车对烟气控制的影响[J]. 铁道学报, 2010, 32(5): 136.LI Yingzhen, LEI Bo. Influence of train on control of smoke flow in small scale tunnel fire experiment [J]. Jouranl of the China Railway Society, 2010, 32(5): 136.
[17] YI L, XU Q, XU Z, et al. An experimental study of critical velocity in sloping tunnel with longitudinal ventilation under fire[J]. Tunnelling & Underground Space Technology, 2014, 43: 198.
[18] 翁庙成, 余龙星, 刘方. 地铁区间隧道的烟气逆流长度与临界风速[J]. 华南理工大学学报 (自然科学版), 2014, 42(6): 121.WENG Miaocheng, YU Longxing, LIU Fang. Smoke backlayering length and critical wind velocity in a metro tunnel [J]. Joumal of South China University of Technology (Natural Science Edition), 2014, 42(6): 121.
[2] HU L H, HUO R, CHOW W K. Studies of buoyancy-driven back-layering flow in tunnel fires[J]. Experimental Thermal & Fluid Science, 2008, 32(8): 1468.
[3] 赵望达, 李洪, 徐志胜, 等. 铁路隧道火灾中烟气逆流层长度的研究[J]. 防灾减灾工程学报, 2010, 30(3): 246.ZHA0 Wangda, LI Hong, XU Zhisheng, et al. Study of backflow distance of smoke under the fire situation in railway tunnel[J]. Journal of Disaster Prevention and Mitigation Engineering, 2010, 30(3): 246.
[4] 姜学鹏, 胡杰, 徐志胜, 等. 铁路隧道火灾烟气逆流的计算模型[J]. 中南大学学报(自然科学版), 2011, 42(9): 2837.JIANG Xuepeng, HU Jie, XU Zhisheng, et al. Computation model for back-layering flow of fire smoke in railway tunnel[J]. Journal of Central South University(Science and Technology), 2011, 42(9): 2837.
[5] LI Y Z, LEI B, INGASON H. Study of critical velocity and back-layering length in longitudinally ventilated tunnel fires[J]. Fire Safety Journal, 2011, 45(6/8): 361.
[6] CHEN L F, HU L H, TANG W, et al. Studies of buoyancy driven two-directional smoke flow layering length with combination of point extraction and longitudinal ventilation in tunnel fires[J]. Fire Safety Journal, 2013, 59(7): 94.
[7] CHEN L F, HU L H, ZHANG X L, et al. Thermal buoyant smoke back-layering flow length in a longitudinal ventilated tunnel with ceiling extraction at difference distance from heat source[J]. Applied Thermal Engineering, 2015, 78: 129.
[8] YAO Y, CHENG X, ZHANG S, et al. Smoke back-layering flow length in longitudinal ventilated tunnel fires with vertical shaft in the upstream[J]. Applied Thermal Engineering, 2016, 107: 738.
[9] TAKEUCHI S , AOKI T , TANAKA F , et al. Modeling for predicting the temperature distribution of smoke during a fire in an underground road tunnel with vertical shafts[J]. Fire Safety Journal, 2017, 91: 312.
[10] GUO Q H , ZHU H H , YAN Z, et al. Experimental studies of the gas temperature and smoke back-layering length of fires in a shallow urban road tunnel with large cross-sectional vertical shafts[J]. Tunnelling & Underground Space Technology, 2019, 83: 565.
[11] 孙振东.因次分析原理[M].北京: 人民铁道出版社, 1979.SUN Zhendong. Principle of dimensional analysis[M]. Beijin: People′s Railway Publishing House, 1979.
[12] BAUM H R. Private communications[M]. Maryland:[s.n.], 2000.
[13] 祝实, 霍然, 胡隆华, 等. 网格划分及开口处计算区域延展对 FDS 模拟结果的影响[J]. 安全与环境学报, 2008, 8(4): 131.ZHU Shi, HUO Ran, HU Longhua, et al. Influence of mesh grid and computational domain on FDS simulation[J]. Journal of Safety and Environment, 2008, 8(4): 131.
[14] MCGRATTAN K, MCDERMOTT R, HOSTIKKA S, et al. Fire dynamics simulator version 5 [J]. National Institute of Standards and Technology Special Publication, 2010, 1019(5): 222.
[15] LIN C J, CHUAH Y K. A study on long tunnel smoke extraction strategies by numerical simulation[J]. Tunnelling and Underground Space Technology, 2008, 23(5): 522.
[16] 李颖臻, 雷波. 隧道火灾模型试验中列车对烟气控制的影响[J]. 铁道学报, 2010, 32(5): 136.LI Yingzhen, LEI Bo. Influence of train on control of smoke flow in small scale tunnel fire experiment [J]. Jouranl of the China Railway Society, 2010, 32(5): 136.
[17] YI L, XU Q, XU Z, et al. An experimental study of critical velocity in sloping tunnel with longitudinal ventilation under fire[J]. Tunnelling & Underground Space Technology, 2014, 43: 198.
[18] 翁庙成, 余龙星, 刘方. 地铁区间隧道的烟气逆流长度与临界风速[J]. 华南理工大学学报 (自然科学版), 2014, 42(6): 121.WENG Miaocheng, YU Longxing, LIU Fang. Smoke backlayering length and critical wind velocity in a metro tunnel [J]. Joumal of South China University of Technology (Natural Science Edition), 2014, 42(6): 121.