Development And Experimental Research Of Fixed Local High-pressure Single-phase Flow Water Mist Fire Extinguishing System

The use of water mist(very fine water sprays) for fire suppression is currently receiving increased attention as a replacement technology for halogen-based chemical agent—such as Halon 1301(CH3Br) the manufacturing of which has been banned by the Montreal Protocol due to their high ozone depletion potential. Water mist technology has been found more advantages such as not contaminating the environment, not destroying the ozone layer, not bringing green house effect, extinguishing fasterly, low consumption, and be safe to the man and other protected objects, so it has been received considerable attentions among international fire science research. This thesis focus on the research and development of water mist fire extinguishing system and its key component of swirl nozzle for the purpose of improving domestic development of the high-pressure water mist fire extinguishing technology. The main contents of the thesis are as followed.Firstly, the outline of the water mist fire extinguishing system's development and its current research background are introduced in this thesis. Emphases are put on the overview about the extinguishing mechanisms, technical characteristics and the international status of experimental researches and engineering applications of the system.Based on atomization law, extinguishing mechanism of water mist and the component of water mist fire extinguishing system, marine fixed local water mist fire extinguishing system is developed, the principle of work, main technical parameter and movement process of water mist is expatiated in the thesis.Atomization law and atomization properties of swirl nozzle is elaborated, the formulation of theory of swirl nozzle is given. We analyse atomization properties of swirl nozzle through experiment and simulation. The emphases analyse the characteristic parameter (such as flux, particle size distribution of nozzle) to the infection of atomization properties of swirl nozzle, validates the consistent of theory and experiment. Based on the above analysis, single nozzle and unit nozzle of swirl are designed.Finally, we establish experimental program about liquid fire on the reference of technical specifications for marine fixed local water mist fire extinguishing system)) of ship trade standard of the people's republic of china, and experimented marine fixed local water mist fire extinguishing system. Experimental results show the interrelation of extinguishing properties and fire size, the distribution form of pipeline network, relative position of fire sounce and pipeline network. Th￡se provides practice base for extinguishing a real fire.