Simulation Study On Venturi Tube Of Painted Spraying Room

The Venturi spray booth uses a venturi to atomize water to capture paint mist.The Venturi spray booth is usually in the form of a top-sending wind-sampling type.Compared with the common top-bottomed air-blasting spray booth,the Venturi effect is used to wash water and paint particles through collision,adsorption and condensation into water droplets containing paint mist.When the water droplets pass through the baffles,the water droplets and other moisture containing the paint mist are separated and enter the water tank,and the purified air is exhausted.The pipes are discharged to the outside.The venturi tube plays a key role in the process of capturing paint mist.It is widely used in automobile coating plants.It has important research significance for environmental protection,green development and reduction of air pollution.In this paper,the Ansys Fluent software is used to simulate the venturi of the core part of the Venturi spray booth.The DesignModeler is used to model the venturi tube in two dimensions,ICEM is meshed,and a series of exploration schemes are designed for the Venturi spray booth Venturi.The tube structure is optimized and combined with the characteristics of the internal flow field to obtain the best venturi structure.This paper mainly studies the constriction section of the venturi,the size of the throat,and the internal flow field of the venturi in the grid plate.The specific content is as follows:(1)Modeling with DesignModeler,ICEM meshing,using two-dimensional triangular mesh,combined with momentum conservation law and energy conservation law,physical model chooses mixture model in multiphase flow model,RNG two-equation turbulence model closes Reynolds time-averaged equation,steady-state operation is used in simulation,SIMPLE method is used in pressure-velocity coupling mode,and boundary is adopted.According to one year's practical experience in Design Institute and factory during my postgraduate period,refer to the relevant parameters determined by practical application of Venturi spray booth.By exploring the conditions,it is concluded that the inlet velocity of air is 20 m/s,the inlet velocity of cleaning water is 0.3 m/s,the outlet section is free,the wall function is standard,and the internal area is fluid internal interface.(2)In order to obtain the optimal size of the inverted horn type shrink tube,theoptimal boundary conditions are used to simulate the length of the shrink tube and the angle of the shrink tube.The speed field and pressure flow field are compared and analyzed to obtain the length of the shrink tube(X1).390 mm,shrinkage tube angle(X3)13 °,the shape and size of the shrink tube is the best,which is conducive to the absorption and purification of paint mist.(3)The main part of the venturi tube is used as the main part of the mixing and absorption of the paint mist particles and the washing water particles.The optimal boundary conditions are used to explore the length of the throat and the width of the throat,and the internal flow field characteristics are analyzed to obtain the length of the throat.(X2)162mm,the throat width(X4)198mm air entrained paint mist particles collide with the washing water,friction,atomization,mixing is the most complete,the paint mist purification effect is best.(4)When the cleaning water and the paint-containing mist pass through the venturi paint mist treatment device,due to the sharp change of the flow cross section,a strip-shaped eddy current zone is formed at the shrinkage tube guide plate,and the washing water is more intense and turbulent in the turbulent motion.The drift and diffusion to the shrinkage tube increase the mixing absorption with the paint mist particles.When the fluid passes through the grid,due to the disturbance of the grid,the dynamic pressure and static pressure are accelerated when the fluid passes through the grid of the grid plate.The faster the fluid velocity and direction change,the greater the turbulence,and the position of the grid is explored.It plays an important role in increasing the degree of internal fluid turbulence.Analyze and compare the flow field cloud map.The closer the grid is to the top of the shrinkage tube,the greater the internal pressure difference,and the greater the turbulence of the cleaning water and air.Smaller,the turbulent energy is increased,the single-layer grid is better than the internal pressure field of the two-layer grid,and the single-layer grid is also economically efficient.(5)According to the results of simulation and theoretical knowledge,it can be used to guide the industrial operation of air electrostatic spraying room in production practice.