Experimental study on smoke bifurcation flow in tunnel fire under longitudinal airflow

被引：2

作者：

Zhong W. ^{[1
,2
]}

Duanmu W. ^{[1
]}

Li H. ^{[1
]}

Liang T. ^{[1
]}

机构：

[1] School of Chemical Engineering and Energy, Zhengzhou University, Zhengzhou, 450001, Henan

[2] State Key Laboratory of Building Safety and Built Environment, China Academy of Building Research, Beijing

来源：

Zhongguo Tiedao Kexue/China Railway Science | 2016年 / 37卷 / 02期

关键词：

Bifurcation flow; Longitudinal airflow; Reduced-scale model experiment; Smoke layer; Smoke temperature; Tunnel fire;

D O I：

10.3969/j.issn.1001-4632.2016.02.08

中图分类号：

学科分类号：

摘要：

A series of fire experiments were carried out with a reduced-scale metro tunnel model, the smoke layer characteristics and temperature distribution under different longitudinal wind speed and heat release rate were investigated to validate the generation mechanism of smoke bifurcation flow. Additionally, the variations of critical velocity of smoke bifurcation flow and the critical Richardson number were analyzed. Results indicate that the reverse flow in the upstream of smoke plume impingement region decreases and a hollow zone appears in smoke layer with the increase of longitudinal wind velocity. The smoke bifurcation flow would occur finally when the reverse flow disappears completely. Under larger longitudinal ventilation velocity, a low temperature region appears in the center of tunnel in the downstream of fire source due to the decrease of smoke induced by smoke bifurcation flow. The dimensionless critical velocity of bifurcation flow increases linearly with the one-third power of dimensionless heat release rate. The critical Richardson number is not affected by dimensionless heat release rate basically and can be regarded as a constant of 0.095. The variations of critical velocity and the critical Richardson number obtained from tests agree well with numerical simulation results. © 2016, Chinese Academy of Railway Sciences. All right reserved.

引用

页码：56 / 63

页数：7

共 21 条

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