不同通风模式下地铁车站内列车火灾的数值模拟

发生火灾时为乘客营造安全的撤离路径是地铁车站环控系统的重要任务.针对地铁车站环境控制系统设计中常用的两种紧急通风模式,使用计算流体力学(CFD)的方法,采用重正化群(RNG)k-ε双方程湍流模型,分别对地铁车站内列车头部、中部和尾部3个不同火源位置的列车火灾进行了三维数值模拟,得到了不同通风模式下的烟气浓度分布.通过分析和比较,认为在列车头部发生火灾时,仅依靠事故风机难以提供足够的能见度,应同时打开站台下排风系统和车行顶道排风系统辅助排烟,其效果在列车中部火灾模拟中得到了验证.列车尾部发生火灾时,推挽式通风模式的效果稍好于全排风通风模式,但也不够理想.文章为地铁车站环控设计中紧急通风模式的选型提供了参考,并对数值模拟方法在地铁车站环控系统设计中的应用进行了探讨.

Numerical simulation of different ventilation strategy designed for vehicle fire in metro station

Fire safety is an important element of overall system safety for subway station. Two typical ventilation strategies designed for emergency are simulated in three dimensional by numerical method of computational fluid dynamic with Renormalization Group k -8 turbulence model. Three different fire locations are considered. Smoke distribution in platform and tunnel of each strategy is achieved. It is shown that emergency fan is not sufficient to obtain enough visibility without UPE and OTE system when fire occurs at the head of subway train. When the middle of the train get fired, the environment on the platform is accepted, but it is not desirable. The necessity of UPE and OTE system is improved. The application of numerical simulation method in design of environment control system of metro station is evaluated.