公路隧道火灾通风计算的改进

Amelioration of Calculation Method for Ventilation of Highway Tunnel during the Fire

现有的公路隧道火灾通风计算方法,是按正常运营通风设计的风机配置,考虑火灾发生后一定数量风机的损坏,计算火灾情况下能够提供的隧道内风速,用该风速和阻止烟流逆流的临界风速比较来验算火灾时期通风的安全性。但在公路隧道的火灾过程中,火灾烟流阻力确实存在,且对隧道火灾时的烟气流动影响较大。本文将烟流阻力引进传统的公路隧道通风计算中,给出了公路隧道火灾通风时的改进计算公式。通过算例,证明了改进的计算方法更符合隧道火灾时实际概况,为隧道火灾时的通风控制提供了科学依据。

The current calculation method for ventilation of highway tunnel during fire has a consideration that with installation of fans for normal operation some fans would be damaged on fire,the wind speed during the fire by other fans working normally in tunnel was compared with critical wind speed,which was enable to prevent the upstream flow of the smoke thus to check the security by ventilation during the fire. There is existed smoke resistance on fire and it has an effect on smoke flowing in tunnel. In this paper,the ameliorative calculation method is put forward for ventilation in highway tunnel during fire with considering the smoke resistance. It has been proved by examples that the ameliorative calculational method accords well with the factual situation of fire in tunnel. And it provides scientific basis of ventilation control on fire in tunnel.