Flow Field Simulation And Technological Test Of Optically Coupled Colloidal Three-Phase Jet Polishing

The quick improvement in various fields speeds up the prosperity and development of human's society.In such case,the increasing social demand also makes higher requirements for scientific research.For example,in the field of optics,electronics,the requirements of elements'surface should be limited in 1nm Rms?Root Mean Square?.Because the better quality of surface means better reflectivity,and relatively lower scattering characteristics.Take hard brittle crystalline material,a popular material in the scientific research,as another example,during the operation,besides the extremely low roughness,the complete lattice is also required.Therefore,as a high precision surface which is characterized by its extremely low roughness,low surface residual stress,and complete crystal structure,super-smooth surface will play a wide role in high-tech industry in the future.So its processing method is also important.As a ultra-precise way of processing,nanoparticle colloid jet polishing induced by UV-light plays an important role in processing element's super-smooth surface.The theory of its processing skill is that nanoparticle and hydroxy in colloid firstly make crash response with atom of functional element's surface successively.Then these atoms can be removed due to jet flow and viscous effect of colloid.The UV-light plays a role in two aspects:firstly,it can be absorbed by nanoparticles to improve their activity;secondly it can work as catalytic light field to speed up the reaction process.In view of the shortcomings of the previous research on polishing technology,such as low processing efficiency and the inability to recycle colloidal polishing fluid,this paper's main researches are as follows:?1?Based on the theory of fluid dynamics,the paper makes CFD models using cone column-shaped light-liquid coupling nozzle and cosine-shaped light-liquid coupling nozzle respectively.Then,three-phase flow simulations will be made though Fluent on those models'inner and outer flow field under the non-submerged condition.So the variables like flow tracks of nanoparticle,colloid's velocity and dynamic pressure of those two kinds of nozzles will be recorded.Particularlly,the variables like colloid's velocity and dynamic pressure in the dynamic pressure region of workpiece's surface will be emphasized.By analyzing two results of three-phase flow simulations,the paper will conclude the different characteristics of two kinds of jet flow fields.Those researches will make a foundation for a suitable light-liquid coupling nozzle for UV-light induced nanoparticle colloid jet polishing system.?2?In the process of UV-induced titanium dioxide nanoparticle colloidal jet processing,along with the polishing process,the surface of TiO₂ nanoparticle colloid will absorb a layer of atoms from processed workpieces.Therefore,the activity of TiO₂ nanoparticle colloid will be influenced.In order to realize the recycling of the titanium dioxide nanoparticle colloid after processing,a set of titanium dioxide nanoparticle colloidal activation process system based on O₃/UV advanced oxidation method was designed.The activation performance of the system was analyzed by flow field simulation.?3?On the basis of UV-light induced nanoparticle colloidal jet polishing system,using anatase titanium dioxide nanoparticle colloidal as polishing fluid,two kinds of light-liquid coupling nozzles were used to polish the surface of monocrystalline silicon,and the sub-nanometer super-smooth surface was obtained.At the same time,visible light activity comparative experiments and characteristic experiments of newly-made anatase titanium dioxide nanoparticle colloid will be made.By doing so,the result of simulation on two kinds of nozzles will be found and catalytic performance of newly-made colloid will be tested.