复杂公路隧道火灾风网稳态求解模型及应用

Steady calculation method and its application of complex highway tunnel's fire ventilation network

为计算火灾情况下复杂公路隧道中风流的温度与流量,分析了以质量流量为未知数、含交通风压的隧道风网稳态分风模型。基于隧道围岩与烟流的稳态换热得到隧道风温的计算式,并用平均风温计算各段隧道的热风压。给出了用网络解算与稳态换热迭代求解热风压的流程。针对此模型,编制了相应计算软件,并对50MW火灾下某平导半横向式通风隧道进行了计算,对隧道有效求援时间以及控风措施进行了分析。结果表明:隧道热风压与隧道分配到的风量存在相互依赖关系,采用迭代求解提高了风量与热风压的计算精度;依据此模型开发的软件可以方便地对任意复杂隧道、在任意位置发生火灾时的通风系统进行计算,有助于隧道设计与运营管理中对火灾应急预案的制定。

Aiming at the calculation of temperature and air flow amount in a highway tunnel on fire,a steady allocation method of air flow in a tunnel network with the mass flow as unknown and traffic wind pressure was analyzed.Based on the steady heat transfer between surrounding rock and smoke flow,the calculation equation of tunnel＇s air flow temperature was derived.Under the conditions of fire,the heat wind pressure in each part of a tunnel was obtained by adopting the average air flow temperature.The iteration process between a ventilation network calculation and a steady heat transfer for the heat wind pressure was presented.The software of this model was also programmed and applied in a parallel-heading and semi-transverse ventilation tunnel on a 50MW fire.As a sample,the time for rescue and measurement for controlling the smoke flow were analyzed.The results indicate that the heat pressure and allocated air flow amount depend on each other,so the calculation precision of heat wind pressure with iteration can be improved;the software based on the model makes it easy to calculating an arbitrary complex tunnel on fire which occurring in any location of the tunnel,so this helps to constitute the fire schemes during the designation and operation management of a tunnel.2 tabs,7 figs,11 refs.