The Designing Of Polyurea Spray Airbrush And Simulation Analysis Based On Fluent

With the acceleration of industrialization and urbanization,the expectations and requirements of coating technology become more and more higher.Among them,polyurea spray technology has been widely used in the manufacturing process because of its excellent performance.However,when the two components of polyurea coatings are not fully mixed,the coating quality is exceptionally poor.As well as the reaction rate of two components of polyurea coatings is so fast,that they can not be mixed in advance.They must be mixed in the spray gun,and then quickly ejected,so the spray gun plays an important role in improving the mixing effect and spraying quality.Therefore,it is of great significance for the research and development of spray gun.At present,polyurea spray gun generally accept first stage and single T structure,which is eaasily cause incomplete chemical reaction,and reduce the spraying effect.At the same time,the conventional cleaning system often leads to the spray gun cleaning is not thorough,so that the inner part of the spray gun is corroded,thereby shortening the service life of the spray gun.In order to improve the mixing and cleaning effects of the spray gun,can be more convenient adjust the feed of coating material and change the shape of spray drawing,in this dissertation,after the polyurea spray technology were analyzed,based on the theory of impinging stream,a new polyurea spray gun was designed.The mixing chamber of this pray gun adopts two stage impacts mixing,and the two stage impacts were divided into two groups of T and two groups of Y type impinging mixing structure,and the cleaning system used two high pressure air inlets(T type),material supply device and tomization-regulator system were improved too;After that,the whole 3D model of the spray gun was established by Solidworks;Then by using FLUENT fluid analysis software,simulation comparison was done between the new-type spray gun mixing chamber and cleaning system and the traditional spray gun structure.And the benefits of improved system was demonstrated from the velocity,pressure,turbulence intensity,micromixing time,etc.The work will provide a convenient reference for the design of polyurea spray gun and the research on other impinging stream mixer.The results show that the mixing and cleaning effects of the new-type polyurea spray gun have been a qualitative leap by improving the structure of the spray gun.The Reynolds number of the mixed polyurea material in the spray gun is much larger than 2320,which can achieve a great atomization effect;The total time of the fluid in the spray gun is about 5.71 ms,and the micro mixing time of the fluid in the first and second mixing chamber is about 0.89 and 0.32 ms,respectively,both them less than 1 ms,The utility model can meet the requirements of polyurea material mixing with quick reaction and short curing time,so it can satisfy the mixing requirement of the polyurea material which has the characteristics of quick reaction and short curing time;The pressure of the fluid are fluctuate in a violence way of both the first and the second impact areas,however,it is evenly distributed between 5.58 and 5.92 Mpa in the material diversion channel,accordingly,that the design of the diversion channel of new-type spray gun is reasonable,on the other hand,its structure also increases the impact strength;The mixing effect of the first impact area of 2T+2Y mixing chamber is obviously better than 1-1T mixing chamber,as well as the mixing effect of the second impact area is obviously better than the first impact area of 2T+2Y mixing chamber,so the more multiplicity the mixing stages and impingement modes of T types and Y types are,the better mixing effects of the impinging streams mixing chamber will be;The mixing area of the polyurea material is mainly concentrated in the impinging zone,but not in other regions such as the diversion pipe;Compare with traditional cleaning system for one high pressure air inlet,the cleaning system for T type high pressure air inlets greatly improves the cleaning effect,besides,inlet radius of 1.8mm is able to meet the higher cleaning requirements.