Study on the design method of smoke extraction mode of one-way large-space point in tunnels
The key smoke exhaust mode with a space between exhaust ports 60 m and at least 3 openings has been widely used in tunnels.In view of the problems of the current key smoke exhaust mode,such as a large number of smoke vents due to small spacing of smoke vents,large air leakage,and inaccurate opening and positioning of smoke vents,a new one-way point-type smoke extraction mode with large spacing is proposed:a large area of smoke vents is set at an interval of more than 60 m in the flue,longitudinal ventilation is provided on the upstream side of the fire source,and a smoke outlet(including multiple smoke exhaust valves)is accurately opened on the downstream side.To ensure the safety of personnel evacuation and the effectiveness of smoke exhaust,the smoke spreading range,evacuation environment,and smoke exhaust efficiency are selected as the evaluation indexes,and the effectiveness evaluation model of one-way large-spacing point smoke extraction mode is constructed.Considering the interrelation between the parameters of the smoke exhaust system,based on the special fire control design idea,the optimization design method of one-way large-spacing point smoke extraction mode is proposed.Under the premise of ensuring evacuation safety and effective smoke exhaust,the optimization design method and the actual project of the Second Undersea Tunnel in Qingdao Jiaozhou Bay are used to study the new point smoke exhaust mode through numerical simulation,and the influence of different numbers of smoke exhaust valves,longitudinal wind speed,exhaust outlet spacing and slope on the smoke control effect is discussed.The research results show that:Considering the most unfavorable fire source power of 50 MW in tunnel fire,it is recommended that the longitudinal wind speed is 3.67 m/s,one exhaust port(including 12 exhaust valves),and the distance between exhaust ports is 300 m.The reasonableness of the new point-type smoke extraction design is verified by using the reduced size model test with a similarity ratio of 1∶11.
safety engineeringtunnel fireone-way large-spacepoint-type smoke extractiondesign methodevaluation model
万方数据
维普
