Study On The Control Of Ventilation Velocity Of Fire In Highway Tunnel Based On The Safety Evacuation

In recent years, with the highway tunnel construction booming, the number of tunnelsand mileage increasing and the length of the tunnel continuing to make breakthroughs,favorable conditions of highway traffic are created, while different kinds of potentialaccidents have continued to increase, among which the tunnel fire accidents often occur. Oncetunnel fire happens, the temperature and smoke will have a serious threat to personnel security,even the slightest mistake will cause death or serious casualties and property losses. Therefore,the research for the control ventilation velocity in the tunnel fire escape is increasinglyimportant in the tunnel fire safety.Firstly, referring to the relevant literature, on the base of analyzing the advantages anddisadvantages of various commonly used heat release function, the heat release function ofhighway tunnel fire given by Yang Tao is selected in this paper. Secondly, use the CFDnumerical simulation method, for rectangular, circular, horseshoe-shaped tunnel in thedifferent lanes, different heat release rate and different longitudinal ventilation velocity, tostudy and analyze the fire temperature field and the distribution of the smoke field. Finally,choose the control of tunnel smoke reflux and the correction of Cranee formula as a criterion,to research the conditions of fire evacuation. The results show that for rectangular tunnel,two-lane’s control ventilation velocity for20MW fire should not be less than3m/s, three-laneand four-lane not less than2.5m/s, while the30MW fire all not less than3.5m/s; for circulartunnel, the control ventilation velocity for20MW fire should not be less than3.5m/s, for30MW fire two-lane’s control ventilation volecity should not be less than4m/s, boththree-lane’s and four-lane’s not less than3.5m/s; for horseshoe-shaped tunnel, the controlventilation velocity for20MW fire should not be less than3.5m/s, while for30MW firetwo-lane’s control ventilation volecity should not be less than4m/s, three-lane’s andfour-lane’s not less than3.5m/s.This paper indicates different control ventilation volecity to ensure safe escape in the fireand provides a useful reference for the formulation of the tunnel fire emergency rescue planby the study of tunnel fire for different tunnel section.