Research On Fixed Type High Pressure Water Mist Fire Fighting System In Tunnel

Water mist fire fighting system has the advantages of less water consumption, environmental friendliness and high efficiency.Water mist fire fighting technology achieves a lot of developments in the recent decades.With the development of high-grade highway,and specially high-grade highway construction in the mountain terrain,long-large road tunnels are more and more.As a kind of particular building, road tunnel has the features of complicated construction,enclosed environment,heavy traffic,personnel crowded,where it exists fire which is caused by vehicle collision, combustible and explosive chemical article,short-circuit of electrical circuit and so on. Once fire happens in the tunnel,heavy smoke diffuses from the source of fire to all over the place,which is removed hardest.It makes escape and rescue work difficult,causes a lot of people casualty and huge breakage of the body and the ancillary facilities of tunnel and brings bad social influence.Therefore,it is necessary to study fixed type high pressure water mist fire fighting system in tunnel.In this thesis,with fixed type high pressure water mist fire fighting system in tunnel as the research object,method of principle analysis,simulation and doing experiments have been utilized to research on tunnel fire,fire detection technology,total design of water mist fire fighting system and assembled high pressure water mist nozzle. In the chapter one the current situation and features of tunnel fire and the disadvantages of conventional fire fighting system are expounded,and the advantages of water mist fire fighting system in tunnel are analyzed,and the current situation of water mist fire fighting system and nozzles at home and abroad is summarized.In the chapter two the definition,atomization mechanism and extinguishing mechanism of water mist are expounded.At the same time the features of water mist fire fighting system is compared with those of other fire fighting systems.In the chapter three the FDS software is used to simulate fire environment in tunnel,the smoke flow rules and temperature field variations are studied to supply proper theoretical guidance for design of the fire detection and fire fighting system.In the chapter four according to the results of fire simulation the fire detection and alarm system in tunnel is designed.The kinds and installation site of fire detectors are determined.The detection circuit and signal transmission circuit are drew.At last tunnel fire IP camera monitoring system is designed.In the chapter five according to the features of fire in tunnel and the fire fighting design code the water mist fire fighting system in tunnel is designed and control program is raised.In the chapter six the jet flow theory is discussed,and according to actual demand of fire fighting in tunnel and design theory of high pressure water mist nozzle a new type structure of assembled high pressure water mist nozzle is proposed,and it is developed,and at last atomizing experiments and fire fighting experiments are conducted.