侧部点式排烟隧道火灾临界风速研究

为得到侧部点式排烟模式隧道火灾临界风速无量纲计算式,针对隧道侧部点式排烟模式,根据π定理和相似理论,采用量纲分析方法分析影响临界风速的相关因素,推导出影响临界风速3个因素的无量纲函数关系式;采用数值模拟方法,确定临界风速与火灾热释放速率、排烟量、排烟口距火源距离的量化关系.研究结果表明:当无量纲排烟口距火源距离小于2....

Study on critical velocity of lateral point smoke extraction tunnel fire

In order to obtain dimensionless formula to calculate critical velocity of tunnel fire in lateral point smoke extraction pattern,dimensional analysis was made on relevant influencing factors of critical velocity according to π theorem and similarity theory,and a dimensionless functional relation of three influencing factors were derived. Then, numerical simulation was conducted to define quantitative relationship between critical velocity and fire heat release rate,smoke exhaust volume and distance between smoke vent and fire source. The results show that when distance between dimensionless smoke vent and fire source is less than 2. 22,critical velocity increases along with increase of distance by 1/25 power,but decreases along with increase of smoke exhaust by-3/50 power. However,when it is greater than 2. 22,critical velocity no longer changes with either distance or smoke exhaust. Meanwhile,with increase in heat release rate,it always rises by 1/3 power.