Numerical Simulatition Study On Ventilation During Fire In Double Long Highway Tunnel

When one of the double long highway tunnels is on fire, the ventilation network's operational state of the tunnels is vital for fire safety in tunnels after the transverse alleyways has been opened for resue and putting out fire. In this paper, the focus is placed on the fire ventilation in the Extra-long Qinling Zhongnanshan highway tunnel adopted with longitudinal ventilation system. Compared with the related model experiment, the ventilation network's parameters of three-dimensional numerical results about the velocity field, temperature field and pressure field in the tunnel during fire are simulated using Computational Fluid Dynamics (CFD). Based on evaluating the performances of smoke movement control on various longitudinal ventilation programs in the tunnel when the transverse alleyways are opened, some suggestions are put forward for ventilation organization of the tunnels with the transverse alleyways during fire.Firstly, the paper introduces the characteristics, causes, damages, ventilation principle and the current research statue of the tunnel fire. Then, based on the conservation laws and chemical reaction laws, the three-dimensional physical and mathematical model of the smoke movement in tunnel fire was established. Finite volume method was used to discretise the governing equantions and the SIMPLE algorithm was employed to solve the disctretised equations. Compared with the related model experiment, the three-dimensional results of the various longitudinal ventilation programs in the tunnel with opened transverse alleyways are simulated. On the basis of this, the parameters of the velocity field , temperature field and pressure field in the tunnel are analysed in detail. Also, the paper indicates that the distance between the fire and the nearest transverse alleyways upward it would influence the effect of the smoke control in the tunnel when the open-up ways of transverse alleyway are different. Finally, the effects about the smoke control influenced by the transverse alleyway downward fire are...