Study On Atomization Characteristics And Effectiveness Of Two-phase Flow Atomizing Nozzle

Bubble atomizing nozzle is a new atomizing nozzle in recent years.Compared with the conventional atomizing nozzle,it has been paid more and more attention because of its simple structure,low pressure,small gas consumption and high atomization quality.In this paper,based on the original bubble atomization nozzle,the influence of injection hole diameter,mixing cavity length and nozzle diameter on bubble atomization characteristics is qualitativety analyzeed.In this paper,the core components of bubble atomization nozzle are designed and processed,including 3 different nozzle diameters 3 different diameter injection holes and 3 different length injection copper tubes.27 nozzles assembled with different core components.A special test bed was set up for cold test.The particle size,atomization angle,fog flux and droplet velocity at the nozzle outlet were systematically studied.The experimental results are analyzed theoretically,and three kinds of bubble atomization nozzle structures with good atomization effect are selected.Furthermore,under the same gas-liquid mass-flow ratio,the droplet size decreases with the increase of N2 injection pressure,and the larger the diameter of injection hole and nozzle,the smaller the droplet size,that is,the higher the atomization quality.The larger the mixing cavity length,the greater the gas energy loss and the lower the atomization quality.A numerical simulation was carried out using FLUENT software to simulate the volume concentration distribution,pressure distribution,velocity distribution and bubble flow in the gas-liquid two phases inside the nozzle.The simulation results have certain significance for the application of bubble atomization nozzle in reality.Finally,the thermal state test is carried out to explore the fire extinguishing effectiveness of the selected bubble atomization nozzle and the fire extinguishing effect of the different fire source position,to obtain the optimal bubble atomization nozzle parameters and to analyze and explore the bubble atomization fire extinguishing mechanism.