隧道火灾相向射流排烟系统烟气质量流率比例系数
Proportion coefficient of mass flow rate of smoke from a tunnel fire in an opposite jet smoke extraction system
王永东 1任雨桐 1赖宜 2胡志豪 1史林猛 1薛威1
作者信息
- 1. 长安大学公路学院,西安 710064
- 2. 长安大学公路学院,西安 710064;中建四局投资发展公司,广州 510000
- 折叠
摘要
为探究隧道相向射流排烟系统中火灾发生时烟气的流动特性,通过FDS数值模拟研究隧道内不同上、下游风速工况下的上、下游烟气质量流率变化.基于等效风速、理论分析和数值模拟结果得到上、下游风速与烟气质量流率比例系数的关系式.结果表明:当等效风速小于临界风速时,上、下游烟气质量流率比值和烟气质量流率比例系数随等效风速增加而减小,并且等效风速与上、下游烟气质量流率比值存在线性关系;当等效风速大于临界风速时,上、下游烟气质量流率比值和烟气质量流率比例系数为0.
Abstract
To investigate the flow characteristics of smoke during a fire in a tunnel opposite jet smoke extraction system,and to provide a reference for the design of longitudinal airflow velocity to control smoke spread under opposite jet smoke extraction conditions,the variation of upstream and downstream smoke mass flow rates under different upstream and downstream longitudinal velocities in the tunnel were investigated through FDS numerical simulations.The concept of equivalent velocity was proposed,and the equivalent velocity values under different opposite jet longitudinal velocities were obtained by numerical simulation,and the relationship between the equivalent velocities and the upstream and downstream longitudinal velocities was established.Based on the theoretical analysis and numerical simulation results,the relationship between the upstream and downstream longitudinal velocity and the smoke mass flow rate proportion coefficient was obtained.The results show that the temperature decay coefficients vary in three stages with the increase of the equivalent velocity,which can be divided into a low-velocity stage,medium-velocity stage,and high-velocity stage according to the velocity.The upstream and downstream smoke mass flow rate ratios and proportion coefficient show a two-stage variation with increasing equivalent velocity.When the equivalent velocity is less than the critical velocity,there is a linear relationship between the equivalent velocity and the ratio of upstream and downstream smoke mass flow rate,and the upstream and downstream smoke mass flow rate ratios and proportion coefficients decrease as the equivalent velocity increases.When the equivalent velocity is greater than the critical velocity,the back-layering length is zero and the upstream and downstream smoke mass flow rate ratio and the smoke mass flow rate proportion coefficient are zero.
关键词
安全工程/隧道火灾/相向射流排烟系统/数值模拟/烟气质量流率/比例系数/等效风速Key words
safety engineering/tunnel fire/opposite jet smoke exhaust system/numerical simulation/smoke mass flow rate/proportion coefficient/equivalent velocity引用本文复制引用
出版年
2024
NETL
NSTL
维普
万方数据