Influence of tunnel fire doors on the critical supply air velocity at the end of the diversion
When a fire breaks out in a single-hole double-track rail transit tunnel,the personnel are evacuated from the fire upstream through the fire door,and the diversion effect of the fire door will affect the air velocity at the end.The influence relationship is explored by combining theory and numerical simulation.The formula of the end critical blast velocity is derived by theoretical analysis.Using PyroSim software,a full-scale model was established to study the diverting conditions of different number of fire doors,heat release rate and tunnel height.The results show that under the same heat release rate,the diversion velocity of fire doors decreases with the increase of the number of fire doors opened.The diversion velocity of the fire door at the same position increases exponentially with the increase of heat release rate.The total flow rate increases linearly with the prod-uct of the number of fire doors opened and the 0.3 power of the heat release rate,and is less affected by the tun-nel height.Finally,a mathematical model of the end critical air supply velocity was established,which provides a scientific basis for the evacuation and ventilation of the tunnel in case of fire.
fire door shuntcritical supply air velocity at the endlongitudinal ventilationrail transit tunnel
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