Design On Marine Water Mist Nozzle And Experimental Study Of Pool Fire Extinguishing

With the development of water mist fire-extinguishing technology, water mist fire-extinguishing systems has replaced a certain proportion of the former "Halon" fire extinguishing agents products because of its less water consumption, completely clean and the wide range of workloads and applications in the marine fire fighting. At the same time, because of the particularity of fire in ships, the application of marine water mist fire extinguishing systems is becoming a trend in ships and offshore platforms. Due to the immaturity in the domestic and international study on the water mist fire extinguishing technology, both in theories and applications, the practical application has not achieved the desired level, which requires more endeavor. Under this situation, we introduce the jet nozzle theory to analyze the spray theory and atomization process of water mist nozzle, design a new type of water mist nozzles, and set up a test bed of water mist fire extinguishing to process the real experimental research, which will be important to the water mist fire extinguishing technology and further applications.(1) Learning from the analysis on the conventional mechanical atomizing nozzle, we get the reasons the limitation in traditional atomization and spray nozzle in the corner. Through the analysis in spray nozzle atomization by application of jet nozzle theory and swirl nozzle theory, combinated with different nozzle exiting shape method, we improve the original flow to reduce the resistance and design a new nozzle which can meet the requirements of the big spray angle, the distance of spray and the spray particle size uniformity, at the same time, which can reach a large flow to improve the extinguish efficency as well.(2) At the beginning, the traditional water mist spray nozzle and the new one were modeled by using SOLIDWORS software, and the inner flow field model; Then the models were meshed by GAMBIT software; Furtermore, a simulation calculation by FLUNET was processed to study the characteristics of the nozzle and the atomization characteristics under different pressures; Finally, a contrastive analysis was made to contrast them. After what have been done the nozzle structure was optimized, determining the nozzle's working pressure, which not only satisfied the low-pressure spray nozzle requirements, but also owned the more effective capability on fire fighting.(3) A new medium low pressure water mist fire test-bed was designed and built, which can test the temperature of flame and other parts during the whole processes of extinguishing fire test, the analysis of the atomization of the nozzle and fire extinguish process, especially the qualitative analysis of extinguishing oil fire by water mist, was analyzed in this articale. What's more, by making a series of extinguish experiments to study the change of temperature during the process of extinguishing, besides with the factors which affect the fire and the fire-fighting conditions, we obtain some data and image, which provide an important reference to the actual water mist system design and nozzle installation.