Design Of Double Emulsion Drop Forming Chip And Optimization Of Its Working Conditions

Microfluidic technology is an emerging technology with great development prospect in recent years.As the main product of microfluidic technology,microdroplets have been widely used in various fields.At present,there is a great demand for microdroplets in industrial applications(1000 tons/year),and the parallelization of microflow channels can improve the generation rate of microdroplets while ensuring the dispersibility and controllability of microdroplets,so as to prepare microdroplets that meet the requirements of industrial applications.As one of the main microdroplet types,many researchers have studied the chip structure to realize the mass production of double emulsion droplet in recent years.However,the current microchannels used for double emulsion droplet production are complex in structure and occupy a large area,which will undoubtedly greatly increase the production cost of the chip,and is not conducive to the realization of the parallel structure of the chip and a wide range of application.In view of the structural problem,the rapid development of micro-nano scale 3D printing technology in recent years can solve this problem well,but the area problem will greatly increase the printing cost,the cost problem still exists.Therefore,the research on the new double emulsion droplet forming chip has great research value for the mass production of double emulsion droplet.(1)The existing problems of dual-emulsion drop forming chip were analyzed and its structure was improved based on IASE innovation method.The numerical simulation method for microflow analysis is introduced,and the structure of microflow channel for preparing double emulsion droplets and the numerical simulation model are given and verified.(2)The preparation process of double emulsion drops was numerically simulated,and the forming process of two typical flow patterns in the preparation of double emulsion drops was demonstrated.The influences of the velocity of the middle phase,the velocity of the outer phase,the interfacial tension and the viscosity on the forming process and the size of the double emulsion drops were analyzed,and the size range of the double emulsion drops under different flow parameters and physical parameters was given,which provided a reference for the preparation of the double emulsion drops in practical production.(3)The influence of geometrical configuration on the process of double emulsion droplet molding was studied.The influences of inlet Angle,channel width ratio and different expansion angle structure on the process and size of double emulsion droplet molding were analyzed,the size range of double emulsion droplet with different structure was given,and the change of monodispersity of double emulsion droplet with different structure was statistically analyzed,which provided a reference for the design of double emulsion droplet molding chip.(4)A dual-double emulsion forming chip structure is presented.Two basic flow patterns in the preparation process were demonstrated by numerical simulation,and the influences of inner phase channel width,inner phase velocity,interfacial tension and viscosity on the core size of dual-double emulsion were analyzed.The changes of core size under different working conditions were given,which provided a reference for the preparation of dual-double emulsion.(5)In this paper,a double emulsion droplet mass forming structure based on annular array is presented,and the effects of fluid physical properties,flow parameters on the monodispersity in annular parallel microchannels are analyzed by numerical simulation.The stable forming condition range of double emulsion drops and the variation of monodispersity of double emulsion drops under the condition are given.The feasibility of the structure in mass production was verified...