摘要
迄今关于隧道火灾临界风速的研究多在隧道内不存在或存在小阻塞物的情况下进行,现有的临界风速预测模型对于隧道内存在较大阻塞物情况下的火灾烟气控制的适用性尚需验证。然而,地铁隧道中列车截面通常占据隧道横断面很大的比例,相应隧道断面阻塞比下的火灾试验研究并不多见。因此,根据相似理论搭建了1∶10缩尺寸矩形隧道试验模型,进行了无阻塞及断面阻塞比为20%、30%、40%、50%、60%情况下的油盘火试验,并利用数值模拟复现了试验,利用临界风速实测值和模拟值对现有的临界风速预测模型进行了适用性验证,并且研究了阻塞情况下的临界风速随阻塞比、火源释放速率等的变化规律。结果表明,随阻塞物占据隧道断面积比例增大,临界风速明显呈线性下降趋势,基于试验数据分析,得到了阻塞情况下的临界风速预测模型,并进一步利用现有全尺寸隧道火灾试验数据验证了该模型的可靠性。
This paper is aimed at introducing its experimental studies on the critical ventilation speeds for tunnel fire smoke control under blocked and block-free conditions.So far as we know,most case studies have been done involving the tunnel smoke-fire control under such conditions in the minute blockage ratios.Nevertheless,the cross-section size of the subway car bodies may account for up to 50% of those of the subway tunnels.Therefore,it is badly in need of further investigations on the applicability or availability of the existing critical velocity predicting correlations for the fires in the actual tunnels with large blockage ratios.To this end,this paper has turned up to a 1/10 scale model tunnel with the rectangular section in terms of the similarity theories,in which fire tests were conducted under blocked and block-free conditions with the blockage ratios of 20%,30 %,40 %,50% and60%,with the critical velocities obtained for 55 experiments conducted,including 15 under the block-free conditions and 40 under blocked ones.What is more,the experiments we have done have been reproduced via dynamic simulations using the software of FDS.The results of the critical velocity and temperature distributions along the tunnel ceiling obtained through simulations are well in accord with the measured data.This proves that the FDS simulations are realistic and can therefore be adopted for further studies for the similar nature.Therefore,first of all,it can be said that the existing correlations for the critical velocity smokefire prediction and control in the tunnel case without blockage have been testified and modified by the experimental data.Then,we have carefully studied how the critical velocities vary with the blockage ratios and HRRs under the blocked conditions.Our findings have shown that the increase in the tunnel blockage ratio tends to bring about a decrease in the critical velocities required in a remarkable linear relation.That is to say,the decreasing ratio of the critical velocity is nearly equal to the correspo
出处
《安全与环境学报》
CAS
CSCD
北大核心
2016年第3期62-68,共7页
Journal of Safety and Environment
关键词
安全工程
隧道火灾
临界风速
阻塞比
模型试验
safety engineering
subway tunnel fire
critical velocity
blockage ratio
model experiment
