| Given the advantages of environmental protection and high efficiency, advanced water mist fire extinguishing technology has become the main technology of modern fire extinguishing and has been applied in a wide range of fields. The second generation of water mist fire extinguishing technology---ultra-fine water mist has drawn considerable attention. Because the size of the droplets is less than 50μm, less weight, more easily suspended, better mobility, and ultra-fine water mist can flow easily and bypass obstacles to reduce the power of the fire source. A high concentration of droplets can suspend for a long period of time in the space, volume expanded 1700 times after heat, reduce the oxygen concentration in the combustion region, accelerated cooling of flames. At the same time, ultra-fine water mist has good heat-absorbing properties. Its large surface area can speed up the cooling of smoke and absorb the thermal radiation of flames. In addition, compared with a conventional fine water mist, ultra-fine water mist consumes less water and is much safer in electrically charged spaces.Based on the advanced fire protection technology in the paper, the ultra-fine water mist generation systerm was maken according to the ultrasonic atomizing mechanism. The diameter and the mass fraction of the ultra-fine water mist were measured.Through a fog droplet of force and motion process analysis, obtained the fog field maximum mass per unit volume after calculate and the related factors affecting, for improving atomization device doing good preparation in experiment. After the tests, reach a conclusion of flame temperature field and shape structure changes,The experimental platform for the ultra-fine water mist restaining gas burning in face was built. By changing the face of ventilation, fogging rate and gas volumetric flow representative fire development stage, the experiments were done in the different experimental conditions. Experimental results show that absorption cooling and replacement air play an important role in the whole process of inhibition.A numerical model based on experimental cases was developed to simulate the interaction between the ultra-fine water mist and gas burning in the face. The process of ulra-fine water mist restraning gas burning fire systerm was analyzed through the experimental phenomenon and simulated outcome. The simulation confirmed the experimental result, and it showed that heat absorbing and replacement air function played an important part in the ulra-fine water mist restraining gas burning fire system.
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