| With the large-scale development of fire extinguishing technology,Halon fire extinguishing agent is banned by international associations due to its great ozone depletion and serious environmental iMPact.More and more halon alternative technologies have gradually entered the market for extinguishing various types of fires.Common technologies include foam and inert Gas,ultra-fine dry powder and water mist fire extinguishing systems,in which water mist fire extinguishing technology is widely used in various fields with advantages such as high efficiency cleaning.This paper introduces the development process and realization principle of the water mist fire extinguishing technology,and explains the advantages and disadvantages of the existing water mist fire extinguishing technology.On the basis of the experiment,a new type of water mist fire extinguishing system is designed-compressed air pre-mixed Fan spray system.This article focuses on the analysis of the atomization and fire extinguishing characteristics of the compressed air-water premixed fan spray,and through experiments,the fire extinguishing system is realized.Finally,the FLUENT numerical simulation software is used to simulate the performance of the compressed air premixed fan spray.The results of the three experiments have obtained the best parameters of the compressed air-water premixed fan spray fire extinguishing technology.In the experimental study of atomization performance,the atomization of the spray system under different gas-water ratios,different types of pre-mixers,different-sized fan nozzles and different slot angles was used for the droplet size analyzer and other measurement tools.By comparing the spray atomization performance under different condition parameters,find out the condition parameters when the spray is in the optimal state,and coMPare it with the high-pressure water spray under the same water consumption conditions.The experimental results show that the best premixer for mixing fan shaped spray is a rotary jet type premixer.When the water pressure is 0.7MPa,the air pressure is 0.6MPa,the water flow is stable at 10L/min,and the air flow is stable at 18 m~3/h,the 3mm aperture fan-shaped multiple nozzle spray with a slot angle of 80°has the best atomization performance and It is significantly higher than the high-pressure water spray atomization performance under the same water consumption.Use the fluid mechanics calculation software FLUENT18.0 to build a three-dimensional model of a fan-shaped nozzle and perform mesh division and boundary setting,and choose DPM model for simulation.Set simulation condition parameters(including air pressure,water pressure,fan nozzle aperture,nozzle slotting angle)which are the parameter under the best atomization conditions obtained in the fan shaped spray experiments.To simulate the effect of fan spray obliquely on the ground at different angle,get the droplet size,spray velocity,spray area and spray trace of the spray at different oblique angle.CoMPared with the high-pressure water mist spray,simulation studies show that the compressed air-water premixed fan spray achieves the best diffusion effect when obliquely angled at 45°,and the droplet size and spray speed are better than the high-pressure water spray under the same water volume condition.Experiments on extinguishing gasoline fires with pressurized gas-water premixed fan shaped spray in standard confined spaces.Collecting fire extinguishing data through thermocouple,flue gas analyzers and other equipment,analyzing the fire extinguishing effects of sprays under different conditions(fan nozzle aperture,oblique angle,etc.),and extinguishing fires with high pressure water spray Effect coMParison.Research shows that the compressed air premixed fan spray with a nozzle diameter of 3.0mm has the best fire extinguishing effect and range when it is obliquely fired at an angle of 45°at an optimal installation height of 2.3m.The fire extinguishing time is less than the high pressure water spray under the same water consumption. |
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