| The mining and production of coal is the main production method of coal mines and the main cause of dust generation during the production process.Large amounts of dust are generated during production processes such as mining,transportation,and storage,and there are various types,among them,coal dust poses the most serious threat,taking efficient dust reduction measures to reduce dust concentration is a crucial treatment method.Air water jet atomization nozzle as the main structural component of atomization and dust reduction technology,compared to other types of nozzles,they have attracted people’s attention due to their good atomization effect,low gas consumption,and simple structure.This article adopts a combination of theoretical analysis,simulation calculation,and experimental research methods,a systematic analysis was conducted on the gas-liquid two-phase atomization jet.The research object is the atomization field generated by the gas-water jet atomization nozzle,introduced commonly used types of atomizing nozzles based on different nozzle classifications of fog flow shapes and atomization methods.A visual monitoring platform was developed and built.On this platform,the macroscopic process of atomization field generated by detachable and adjustable gas-water jet atomization generator was monitored,and the atomization cone Angle was measured by binarization image processing method.The relationship between liquid pressure,gas flow and atomization cone Angle under different structural parameters was analyzed.In order to further explore the evolution law of atomization field formation,acoustic signals transmitted from atomization field to target material were collected by acoustic emission experimental device,using the transformation relationship between time and frequency domains to obtain the impact performance law of the atomization field;using Fluent fluid simulation software to simulate and calculate the internal flow of an air water jet nozzle with a 60°flaring structure at the lower nozzle,the average velocity distribution of gas-liquid two-phase atomizing jet on the outlet section of mixing chamber after mixing with the change of gas supply flow rate is analyzed.The main research content of this article includes the following aspects:(1)Combining the flaring structure of the air-water jet atomizing nozzle and the flow situation of the internal fluid,the fluid area of the nozzle is determined.Based on the basic fluid mechanics theory,the VOF multiphase flow model is selected to determine the solution parameters of the boundary conditions.The internal flow characteristics of the air-water jet nozzle under 60°flaring are analyzed,mainly to understand the flow development in the nozzle under transient conditions and the velocity distribution under steady conditions.In the interior of the gas-water jet nozzle,Inside the gas-water jet nozzle,the maximum average velocity of the two-phase mixture is distributed on one side of the axial center point,The axial inlet pressure has little effect on the velocity of two-phase mixing atomizing field.When the gas supply flow reaches 10 m~3/h,the average velocity at the outlet of gas-liquid two-phase spray jet at the port reaches 815.17 m/s.(2)The different structures of gas-water jet nozzles and the working states under different working conditions can correspond to the frequency and amplitude of acoustic emission.Exploring the acoustic emission signals under different structures and working conditions can obtain the relationship between the atomization field properties and the acoustic emission signals.By changing the expanding structure of the nozzle under the gas-water jet atomization nozzle and adjusting the operating conditions at different impact distances,different characteristic frequencies of acoustic emission signals were obtained.The comparison results show that the noise frequency is 3.75 k Hz-5.85 k Hz,the gas-water jet formation atomization field 10 cm impact distance 14.64 k Hz-19.53 k Hz frequency peak fluctuation,and the impact distance frequency over 10cm is 20.75 k Hz-35.15 k Hz peak fluctuation.The intake volume only affects the amplitude strength and does not affect the frequency domain range.(3)The influence of working and structural parameters on the atomization characteristics of gas-water jet atomization nozzles was studied.Based on the Control variates of single factor,the relationship between the three working parameters of inlet air flow and supply pressure,the two key structural parameters of nozzle opening expansion angle and mixing chamber diameter length,the macro state of atomization field and the two atomization characteristic indicators of atomization cone angle is explored.Under the same liquid pressure,with the increase of air intake,the variation range of atomizing cone Angle obtained by the atomizing nozzle with 60°flanging structure of the lower nozzle increases first and then decreases,and the decrease trend of atomizing cone Angle is extremely obvious.On the contrary,when the lower nozzle is expanded at 100°and 120°,as the system intake flow rate increases to 10 m~3/h,the downward trend of the fan-shaped cone angle formed at the front end of the fog flow slows down.(4)Study the changes in liquid phase volume diffusion to verify the evolution law of atomization cone angle.The ratio R between the liquid volume diffused outside the circular nozzle area of the collector per unit time due to gas incorporation and the initial liquid volume flow of the atomizing nozzle without aeration can directly reflect the atomizing effect of the gas-water jet atomizing nozzle.The change of R can verify the change law of atomization cone Angle characteristics.The larger R is,the atomization cone Angle increases gradually.Under the condition of liquid supply pressure 0.025MPa and gas supply flow rate 9 m~3/h,the maximum R is 53.3%,indicating that the atomization effect is better under this parameter condition. 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