Atomization Characteristics Analysis And Experimental Study On Water Mist Extinguishing Nozzle

As the series of halon fire extinguishing faces limit and elimination gradually,Water mist fire extinguishing technique,with its high efficiency,environmental protection,energy saving,has become main fire extinguishing technology.It is one of the hottest spot in the research of fire science,and water mist fire extinguishing technology at home and abroad has made significant progress.However,water mist fire extinguishing sprinkler is the key part of water mist fire extinguishing system,the traditional atomizing nozzle atomization effect is not ideal.Atomizing angle and protection radius are small,which limits the fine water mist fire extinguishing system application scope.At present,there are many methods to solve such problems as atomizing angle,protection radius and spray momentum,including combined atomization nozzle,rotary spray nozzle,and medium atomization nozzle.These methods are widely used,because the atomization effect is good,and processing production is convenient.In this study,In view of the deficiency of the traditional direct spray nozzle,the job designs a new type of the water mist fire extinguishing sprinkler,and provides a new nozzle water structure,whose characteristic is that inlet channel axis which is arranged beside the center inlet channel axis is particular equal angle,and spins in the same direction.Inlet axial center flow axial momentum in ensuring that droplets are large enough,conducive droplets penetrate the fire reached depths of fire so as to play a better fire-fighting effect on either side of the inlet is to the swirl nozzle cavity formation,to guarantee the droplet has a sufficiently large radial momentum,expanding the spray cone angle,increasing the coverage area.Due to the complexity of turbulent motion and atomization mechanism,researchers should have solid fluid mechanics and mathematics knowledge to establish the physical and mathematical model.At present,there isn't a set of perfect nozzle design calculation procedure;therefore,the experiment research plays a very important role in fine water mist fire extinguishing sprinkler design manufacturing process.In this study,theoretical research,numerical simulation and experimental verification of water mist fire extinguishing nozzle structural parameters to be optimized.By means of CFD software on the nozzle internal and external flow field numerical simulation under different conditions,to discuss the impact of the nozzle structure on atomization performance,using laser Doppler tester and phase Doppler particle measuring instrument the cold nozzle atomization performance test,including the measurement of the characteristic parameters of the flow coefficient,droplet diameter,the atomization cone angle,droplet speed,We obtain water mist fire suppression the optimal structure parameters of the nozzle and working conditions,according to the measured results and numerical simulation results were analyzed,the experiment can drawn a conclusion is that the nozzle is better atomization performance and better momentum indicator with a large axial momentum and radial momentum,it helps realizing the depth fire fighting and expanded fire fighting scope,moreover is small size,structure is simple and processing is convenient,it is a high performance nozzle with the application prospect.