| Dry water is a white powdery new multi-material material with internal distilled water or other solution as the main component and the outer surface uniformly coated with hydrophobic silica.The dry water fire extinguishing agent has excellent fire extinguishing performance.It is different from the traditional dry powder fire extinguishing agent and water mist fire extinguishing agent,combining the advantages of both,and has the combined mechanism of physical cooling and chemical inhibition.In this paper,orthogonal test method is used in the laboratory to prepare a dry water fire extinguishing agent.The high-speed camera,thermocouple and other testing methods are used to study the process of filling fire extinguishing,explosion-driven fire extinguishing,and dry powder fire extinguishing process.Conduct a comparative analysis.The main contents and research results of the thesis are as follows:(1)Using high-speed dispersive stirring method,distilled water or other solution is mixed with hydrophobic silica to make 13 sets of dry water fire extinguishing agent.By appearance observation and microscopic observation,stirring time,stirring speed and water phase and hydrophobicity are used.The mass ratio of silicon oxide is an influencing variable,and the optimum preparation parameters are preferred.The prepared dry water fire extinguishing agent has a particle size mainly distributed in the range of 0 to 400 ?m,and has a stable structure and a good coating effect.At the same time,the dry water fire extinguishing agent under the optimal preparation conditions was added with other modifiers,and the ammonium dihydrogen phosphate dry water fire extinguishing agent,the polyvinyl alcohol dry water fire extinguishing agent and the sodium chloride dry water fire extinguishing agent were respectively prepared.(2)With reference to the national standard for dry powder fire extinguishing agent(GB4066-2017),the physical properties of four typical dry water fire extinguishing agents were tested.The results show that the bulk density of several dry water fire extinguishing agents ranges from 0.511g/ml to 0.653g/ml;The gel-type polyvinyl alcohol dry water fire extinguishing agent formed by adding polyvinyl alcohol has poor fluidity,and several other fluidity are similar;Theprepared dry water fire extinguishing agent is mainly distributed in the range of0-400 ?m,and the addition of polyvinyl alcohol significantly affects the particle size distribution;The dry water fire extinguishing agent has less water loss at 20 °C and more loss at 50 °C;Several groups of dry water fire extinguishing agents have good water repellency and do not interact with external water;the dry water fire extinguishing agent is easily damaged under high pressure environment,and the maximum pressure that can be withstood is about 1.2 MPa.(3)In order to verify the fire-extinguishing performance of the prepared dry water fire extinguishing agent,the test method for the fire extinguishing effect of dry powder fire extinguishing agent was simulated,and the Class A solid fire and Class B liquid fire working conditions were simulated.Select 4 sets of dry water fire extinguishing agent to inject the fire extinguisher cylinder,add nitrogen pressure to1.2MPa,and carry out the spray fire test with ABC dry powder fire extinguishing agent at the same time.The results show that several groups of dry water fire extinguishing agents can effectively extinguish Class A and Class B fires,and have a considerable fire extinguishing effect with ABC dry powder fire extinguishing agent,but the thermocouple recording temperature curve drops more significantly,indicating that the cooling effect of dry water fire extinguishing agent is better.The dry powder fire extinguishing agent is more prominent,and the ammonium dihydrogen phosphate dry water fire extinguishing agent has the best fire extinguishing effect.The analysis believes that the advantage of dry water fire extinguishing agent is that it has both chemical inhibition and physical cooling combined fire extinguishing.The disadvantage is that the structural stability of dry water fire extinguishing agent is limited by the filling pressure.(4)A simple explosive fire extinguishing device was prepared,and the comparison test between the dry fire extinguishing agent with the best fire extinguishing efficiency and the ABC dry powder fire extinguishing agent was carried out.The results show that both the dry water fire extinguishing agent and the dry powder fire extinguishing agent can effectively extinguish the oil fire under the explosion drive,the coating structure is destroyed after the dry water fire extinguishing agent is driven by the explosion,and the water phase and the powder combined with the rapid impact fire source,the fire extinguishing time is the samecondition.The dry powder fire extinguishing agent should be fast.The high-speed camera capture image shows that the dry water fire extinguishing agent has a shorter residence time after the explosion drive,while the dry powder fire extinguishing agent is dispersed in the air for a long time.Explosive-driven dry water fire extinguishing agent is suitable for fast and efficient fire fighting in some special environments such as toxic and radiation environments.Considering that salt water can inhibit the combustion chain reaction,the use of brine as the internal phase material to prepare NaCl dry water fire extinguishing agent has the advantages of high fire extinguishing efficiency and low cost,and has wider application prospects.Figure [63] Table [16] Reference [66]... |
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