| Adhesive spraying is a key technical link in the construction of floor leather for high-speed rail cars.The spray gun used in construction directly affects the spraying quality of the adhesive.When designing the floor leather laying device for high-speed rail cars,due to the limitations of the device design size and the operating space of the car,the spraying of the glue must use an air spray gun with a small external size,a wide fan spray,a short spray distance,uniform spray coating,and low energy consumption.However,it is difficult for commercial spray guns in the current market to simultaneously meet the above requirements.This article redesigns the key component structure of an air spray gun often used in current construction,and optimizes the operating parameters in detail in the spraying operation,so as to effectively improve the spraying effect of the adhesive.First of all,in order to increase the fan surface of the spray gun and improve the spraying quality,the structural parameters such as the liquid nozzle opening diameter of the spray gun,the control angle of the fan surface,and the number of auxiliary atomizing holes were redesigned,and the spray atomizing field was established.The gas-liquid two-phase simulation calculation model was simulated and analyzed.The results show that:increasing the nozzle diameter of the liquid increases the fan width,but the droplets move faster,and splashes easily occur after painting.The optimal nozzle diameter is 1.5 mm.Increasing the angle of the fan to control the hole angle is beneficial.The airflow of the atomization field is expanded,and the fan spray is increased.However,if the angle is too large,the thickness of the liquid film in the middle position will be thinner.The optimal angle of the fan control hole is 65°;increasing the number of auxiliary atomization holes is not conducive to atomization The expansion of the airflow and the increase of the spray width of the field,the optimal number of auxiliary atomizing holes is 2.Secondly,based on the optimized design of the spray gun structure,the operating parameters of the spraying process are obtained through a gas-liquid two-phase simulation calculation model,and the pressure and spraying distance on the spraying quality are obtained by calculating the atomizing flow field under different pressures and spraying distances Impact.The results show that increasing the fan control pressure increases the airflow expansion of the atomization field and widens the fan spray width,but the pressure is too large and the liquid film thickness tends to be thinner on both sides,preferably 1.0 bar;increasing the auxiliary atomizing pressure,The airflow expansion of the atomization field is reduced,and the fan surface spray width is reduced,but the spray quality is improved,preferably 1.3 bar;increase liquid feed pressure,the fan surface spray width is unchanged,the liquid film is thickened,and the coating quality is improved,preferably 1.2 bar;increase the spraying distance,the liquid film becomes longer,and the spraying quality rises first and then decreases,preferably 200 mm.Finally,a set of test prototypes suitable for spray gun spray test was set up,related parameters were set and laboratory spray test was performed.By comparing the simulation results and test results of the shape and size of the liquid film on the spraying surface,the shape of the liquid film on the spraying surface is similar to the simulated shape under the same parameters,and the change trend of the liquid film size curve is the same as the simulation result better.In this paper,the theoretical and experimental researches are made on the structural improvement of the air-assisted atomizing spray gun and the optimization of the spraying operation parameters.The research results have certain practical significance for improving the air-assisted atomizing spray and improving the coating quality. |
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