| Ceramic microsphere is a popular new functional material at present.It has excellent properties such as low density,low thermal conductivity,high strength,high hardness,and is widely used in industrial production.Alumina ceramic microspheres are widely used as catalyst carriers and adsorption materials due to their large specific surface area,excellent pore structure and stability.At present,the main methods of preparing alumina ceramic microspheres have many problems,such as complex process,poor controllability,low sphericity,and difficulty in industrial production.Therefore,it is of great practical significance to study an efficient and simple new method to prepare alumina ceramic microspheres.Based on the micro-droplet jetting technology,a multi-outlet pneumatic injection valve is designed to realize the efficient preparation of alumina ceramic microspheres.The main research work is as follows:(1)This paper analyzes the current preparation methods of alumina ceramic microspheres and their existing problems,studies the characteristics and applications of micro-droplet jetting technology,and proposes a pneumatic mechanical striker micro-droplet jetting technology scheme for the rapid preparation of alumina ceramic microspheres.(2)Design the structure of multi-outlet nozzle and analyze the working principle of multi-outlet pneumatic injection valve.The formation process and force analysis of micro-droplet jetting were analyzed,the critical velocity of micro-droplet jetting was solved,and the approximate calculation formula of micro-droplet jetting velocity and jetting volume was derived.Fluent was used to simulate the fluid,and the influence of nozzle outlet,outlet diameter,striker movement speed,motion stroke,feeding pressure,and solution viscosity on injection performance was analyzed.(3)The structural design of a multi outlet pneumatic injection valve is carried out,and the functions and working principles of its components are analyzed.Conduct force and motion analysis of the injection valve under working conditions,use Adams simulation software to solve the collision velocity and contact force between the striker and the nozzle,analyze the stability of the striker and the dynamic model of the injection valve;Design a gas supply system and control system to form a micro-droplet jetting system.(4)Build a droplet injection experimental test platform,conduct singlefactor comparison experiments,and analyze the injection performance of the injection valve.Design alumina ceramic microsphere rapid prototyping equipment and process,and carry out preparation experiments.The results show that the multi-outlet pneumatic injection valve has good working performance.By this method,alumina ceramic microspheres with a particle size of 100-300μm can be quickly prepared,and the diameter deviation rate is within ±12%,which has good uniformity and sphericity,and can realize industrial production. |
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