Flow Field Simulation And Structure Optimization Design Of Spray Gun For Spraying Equipment

Due to the simple spray paint spraying process,the hand-held spray gun has great flexibility,so it is widely used in real life.However,many problems will occur in the spraying process of the spray gun,such as uneven mixing of the paint,insufficient impact between paint and wall surface.This article is based on the spray gun provided by a research institute in Shenyang to solve the above two problems with the spray gun.By adopting numerical simulation methods and using Fluent software,the spray gun mixing chamber and the nozzle are optimized respectively.The main research contents are as follows:(1)Based on the theory of computational fluid mechanics,the three-dimensional modeling software is used to establish the three-dimensional model of the original fan-shaped nozzle of the spray gun.The analysis shows that the situation is the same as the actual spraying effect,which proves the correctness of the simulation.(2)Based on the structure that mainly affects the spraying of the fan-shaped nozzle:the inner diameter of the nozzle D,the length L of the liquid incident cylindrical section,and the half-angle ? of the V-shaped groove.By using orthogonal analysis design methods,nine different types of nozzles are designed and compared with the original fan-shaped nozzle models.Their velocities,water contents and dynamic pressure values are analyzed.It is found that the water contents of the nozzles of these nine models vary with the distance in the same trend and the spraying range is basically the same;No.8 nozzle,that is,the diameter of the nozzle cavity D=6.94 mm,the length of the liquid incident cylindrical section L=5.24 mm,the half angle of the V-shaped groove ?=30°.Its speed and dynamic pressure are the largest among all types of nozzles.(3)According to the design ideas of the static mixer,two mixing chamber models A and B are established.The A mixing chamber structure is a mixing chamber inserted into a spiral mixing unit,and the B mixing chamber structure is a mixing chamber inserted into a lithographic overlapping unit.Based on the CFD theory,it is imported into Fluent software to analyze the velocity,turbulence intensity,and the concentration of silicate solution.Obtaining the designed A and B models can increase the mixing effect between the two fluids.At the same time,due to the role of the spiral mixing element,the number of vortices and turbulence intensity in model A are greater than that in model B.Among the three models,the region of silicate solution in model A diffuse the most with the change of distance,indicating that it is well mixed with isocyanate solution.In summary,to enhance the mixing effect of the mixing chamber and increase the impact degree of the paint,it is recommended to select the mixing chamber design of the A model spiral mixing unit structure and No.8 nozzle with the diameter of the nozzle cavity D=6.94 mm,the length of the liquid incident cylindrical section L=5.24 mm,the half angle of the V-shaped groove ?=30°.