直立式机械排烟临界排烟口高度  

Critical height of the vertical mechanical smoke vent

作　　者：钟委[1] 吴英昊 田英[1] 高子鹤 ZHONG Wei;WU Yinghao;TIAN Ying;GAO Zihe(School of Mechanics and Safety Engineering,Zhengzhou University,Zhengzhou 450001,China;School of Civil Engineering,Zhengzhou University,Zhengzhou 450001,China)

机构地区：[1]郑州大学力学与安全工程学院,郑州450001 [2]郑州大学土木工程学院,郑州450001

出　　处：《安全与环境学报》2024年第5期1849-1854,共6页Journal of Safety and Environment

基　　金：国家自然科学基金项目(52076198);河南省优秀青年科学基金项目(222300420078);河南省青年人才托举工程项目(2022HYTP019)。

摘　　要：为改善地铁站台的排烟效果,提出了一种在排烟管道顶部上接风管的新型直立式机械排烟。通过数值模拟分析地铁站台火灾时采用直立式机械排烟的效果。结果表明:采用上接风管的直立式排烟相比于排烟管道顶面排烟具有明显优势,其排热量可增加14.51%;直立式排烟存在一个临界排烟口高度,当排烟口高度较低时无法排出顶棚下方的高温烟气,而当排烟口高度超过该临界高度后,受到顶棚的限制其排烟效果反而会下降;临界排烟口高度与排烟风速无关,但受排烟口边长的影响,且在临界高度时排烟口与顶棚间的距离近似等于排烟口边长的一半。To improve the effect of smoke exhaust on subway platforms,this paper proposes a new mechanical smoke exhaust system,which is named vertical mechanical smoke exhaust.The effect of vertical mechanical smoke extraction in subway platform fire is analyzed by a numerical simulation method.The results show that the smoke exhaust effect of the vertical smoke exhaust mode is significantly better than that of the top exhaust mode,and the total heat exhausted is 14.51%higher than that of the top exhaust mode.The reason is that compared with the top exhaust,the vertical exhaust improves the height of the exhaust port,and the height and temperature of the exhaust smoke are increased.Further research shows that there is a critical height of the vertical exhaust vent(CHV).When the height of the exhaust vent is lower than the CHV,the high-temperature smoke under the ceiling cannot be discharged,but when the height of the exhaust vent exceeds the CHV,the smoke exhaust effect will decline due to the restriction of the ceiling.When the height of the exhaust port is high,the distance between the ceiling and the exhaust port is too narrow.In the process of exhaust,the smoke violently collides above the exhaust port and forms a positive pressure vortex near the center of the exhaust port.The vortex cannot exhaust smoke,resulting in a decrease in the exhaust effect.When the length of the side of the exhaust port increases,the heat discharged per unit area decreases.The height of the critical smoke exhaust vent is not affected by the exhaust velocity u,but is affected by the length of the vent side D.The distance l between the vent and the ceiling at the critical height is approximately equal to D/2.

关 键 词：安全工程 地铁站台 直立式机械排烟 临界高度 排烟口尺寸 

分 类 号：X932[环境科学与工程—安全科学] X951