Simulation Analysis And Experimental Research On Spray Performance Of Snowmaker’s Nucleator Nozzl

The nucleator nozzle is one of the most critical working parts of the snowmaker.The atomization and nucleation efficiency of water is determined by the atomization performance of the nucleator nozzle,its atomization performance directly affects the nucleation rate,it also further affects the snowmaking performance and snow quality of the snowmaker.Studying the atomization performance of the nucleator nozzle of the snowmaker is of great significance to increase the nucleation rate and improve the utilization rate of water resources.The nozzle being studied has the characteristics of complex structure,small size,high jet pressure,high jet velocity and high turbulence intensity,thus the atomization performance of the nozzle was studied by numerical simulation method and experimental method respectively.The main research contents are as follows:In this paper,a kind of nucleator nozzle of snowmaker is studied,the 3D modeling of the fluid domain structure in the nozzle and the external spray field structure is made by the Solidworks software,then meshing by the ICED.CFD software.Finally,the mesh geometry model is imported into the FLUENT software,and then calculated after selecting model,setting boundary conditions and setting solution parameters.The research content is divided into three parts:In the first part,the influence of the moving distance of the valve core structure in the nozzle on the atomization performance is studied.The Mixture model and the DPM(Discrete Phase Model)model are selected as the mathematical models.Taking the moving distance d of the valve core in the nozzle as the research variable,there are five groups of working conditions.Afer calculation,the outlet velocity,outlet flow rate,liquid phase velocity distribution and liquid phase composition distribution under different working conditions are obtained,the results of droplet size and number in spray field under different conditions are compared and analyzed.The result shows that:when the moving distance d of the valve core in the nozzle is closer to the minimum value,the liquid jet velocity at the outlet increases,the number of droplets increases,and the atomization performance is improved.In the second part,the influence of the diversion groove on the atomization performance was studied.The VOF(Volume Of Fluid)model and DPM(Discrete Phase Model)model are taken as mathematical models respectively,the 3D modeling of two kinds of nozzles with and without diversion groove are established.The distribution of the pressure field inside the nozzle,the vortex intensity inside and outside the nozzle,and the flow lines inside and outside the nozzle under the two working conditions are calculated.The velocity of liquid phase at the outlet horizontal line,the central axial,as well as the horizontal line with different axial distance in the spray field under two working conditions were analyzed and compared.And the number of the droplet is counted and compared.The result shows that:the diversion groove can reduce the pressure inside the nozzle,decrease the jet axial velocity,increases the radial velocity,spread the spray,increase the atomization cone angle,and increase the average droplet size in the spray field.In the third part,the influence of mixing ratio of water and air on atomization performance was studied.The VOF(Volume Of Fluid)model and DPM(Discrete Phase Model)model are taken as mathematical models respectively.Taking the mixing ratio as the research variable,there are five groups of working conditions.The research method is based on experiment and supplemented by numerical simulation.Firstly,the gas-liquid mixing ratio which can realize artificial snow making is obtained,and the quality of snow making is observed and measured.Then the macroscopic spray characteristics under different working conditions were observed and compared,and the corresponding working conditions were numerically simulated.The result shows that:Increasing the proportion of air can effectively optimize the atomization performance,with the increase of air ratio,the droplets become finer and denser,and the atomization effect is better.When the mixing ratio reaches 0.2,artificial snow making can be achieved at-18℃.The quality of snow is the same as that of natural snowfall,and it is finer and denser,with higher viscosity and humidity.